CA1189648A - Method of preparing polymer lattices of homogeneous interpenetrated structure - Google Patents
Method of preparing polymer lattices of homogeneous interpenetrated structureInfo
- Publication number
- CA1189648A CA1189648A CA000427439A CA427439A CA1189648A CA 1189648 A CA1189648 A CA 1189648A CA 000427439 A CA000427439 A CA 000427439A CA 427439 A CA427439 A CA 427439A CA 1189648 A CA1189648 A CA 1189648A
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- CA
- Canada
- Prior art keywords
- prepolymer
- cross
- basic
- mixture
- linking
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/28—Treatment by wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
- C08J3/243—Two or more independent types of crosslinking for one or more polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
Abstract
P A T E N T
IMPROVEMENTS IN OR RELATING TO METHOD OF PREPARING
POLYMER LATTICES OF HOMOGENEOUS INTERPENETRATED
STRUCTURE.
INVENTION : ALBERT GOURDENNE
PASCAL HEINTZ
ELECTRICITE DE FRANCE (SERVICE NATIONAL) ABSTRACT
A method of preparing polymer lattices of homogeneous interpenetrated structure, starting from a mixture of at least two basic prepolymer constituents is characterised by the fact that a microwave radiation is applied having a frequency spectrum chosen in order that it interacts preferentially with the first prepolymer and a power density chosen in order that it directly activates the exothermic reaction of cross-linking of the first pre-polymer. The cross-linking of the second prepolymer is only triggered under the combined action of the heat due to the interaction of the microwave energy with the second prepolymer and the heat introduced by the cross-linking reaction of the first prepolymer, which makes it possible to combine propagation of the two cross-linking reactions at similar speeds.
IMPROVEMENTS IN OR RELATING TO METHOD OF PREPARING
POLYMER LATTICES OF HOMOGENEOUS INTERPENETRATED
STRUCTURE.
INVENTION : ALBERT GOURDENNE
PASCAL HEINTZ
ELECTRICITE DE FRANCE (SERVICE NATIONAL) ABSTRACT
A method of preparing polymer lattices of homogeneous interpenetrated structure, starting from a mixture of at least two basic prepolymer constituents is characterised by the fact that a microwave radiation is applied having a frequency spectrum chosen in order that it interacts preferentially with the first prepolymer and a power density chosen in order that it directly activates the exothermic reaction of cross-linking of the first pre-polymer. The cross-linking of the second prepolymer is only triggered under the combined action of the heat due to the interaction of the microwave energy with the second prepolymer and the heat introduced by the cross-linking reaction of the first prepolymer, which makes it possible to combine propagation of the two cross-linking reactions at similar speeds.
Description
The presen~ invention relates to a process for preparing polymer lattices of homogeneous inter~enetrated structure, fronn a mixture of a-t least two basic pre-poly~er constituents.
The manufacture of interpenetrated pol~ner la-ttices is usually carried ou-t by the conventional thermal method. This method of activating cross linking reactions of two polymers is tricky because ln order for it to be implemented in a satisfactory manner it involves reaction kine-tics which are similar. In fact, the final structure must be as homogeneous as ~ossible and especi~lly it mllst not inc]u~e islands or zones which are richer in one particular pol~ner, i.é. it is necessary to avoid the phenomenon of phase separation.
Such a result is di~ficult to achieve in practice, for the cross-l~king mechanisms of the t-~ro resins of the basic mixture are of a different -type in the large majority of cases, in such a manner as to avoid covalent chemical bridgings between the two lattices. Further-more, it is practically impossible in practice to makepolymerisation kinetics of the basic prepolymer con-sti-tuents coincide.
The s~lthesis of interpenetrated lattices is usually achieved by means of a thermal activation of the various cross-linking reactions, carried out in an oven or autoclave, and it is extremely rare to obtain homogeneous final structures owing to the difficulties encountered in ~akirl~ the cross-linking speeds coincide.
Usually structures ~!i th phase separa-tion are ob-tained.
This major drawback has~ moreover, considerably lirnited the development of interpenetrated polymer materials~
According to the method of the present invention, a microwave radiation is applied to the basic pre-polymer mixture : this microwave radiation is of a frequency spectrum chosen in order that it may inter~c-t preferentially with the first prepolymer and of a power intensity chosen i.n order that it may directly activate the exothermic cross-linking reaction Df the firs-t pre-polymer, whilst only trlggering the cross-linking of the second prepolymer under the combined acti.on of the heat due to the interaction of the microwave energy with the second prepolymer and the heat introduced by the cross-linking reaction of the first prepolymer, which make the combined prepagation o~ the two cross-linking reactions possible at similar speeds.
According -to ano~ther characteristic of the present invention, the two basic prepolymer cons-ti-tuents are cross-lir,ked according to differen-t polymerisation mechanisms~ In particular, one of the basic pre-polymers can be cross-linked according to a polymerisation mechanism which gives rise to free radicals, whilst the other basic prepolymer can be cross-linked according to a polymerisation mechanism by polycondensation.
I
The prepolymer which becomes cross-linked according to a polymerisation mechanism which gives rise -to free radicals can, for example, be formed with advantage by an unsaturated polyester resin9 especially by a solu-tion of 70% by weight unsaturated polyester resin in a solvent such as styrene1 The prepolymer of the basic mixture which is cross-linked according to a polymerisation mechanism by polycondensation can, for example, be formed to advantage by an epoxy resin, in particular of the type rG~`BA with the addition of a hardener such as diaminodipherylmethane.
Such a mixture of two basic prepolymer constituents can, for example be formed by approxirnately 20C~ by weight of a soltuion of unsatura-ted polyester resin and approximately 80% by weight of ar. epoxide resin with a hardener added.
According to one variant of the process of the present invention9the -two basic prepolymer consti-tuents can also be cross~ ed according to identical poly-merisati.on mechanisms in particular by polycon~ensation.
According to an addi.tional characteri.stic of -the method of preparation of the present invention, the mixture of at least two basi.c prepolymer constituents can, moreover, contain other additivesJ such as a reinforcing charge 9 in particular a mineral charge such as glass fibre.
The method which forms the object of the presen-t ~.3~'q~
invention can be implemented by using either a microwave treatment in a single mode cavity or in multi-mode cavity.
The frequency spectrum of the microwave radiation used, can, for example include frequencies between about 0O5 and about 100 G~z inclusive, pre:Eerably between about 1 and approximately ~GH7 inclusive, and in particular, a fre~uency of the order of 2.5 GHz.
The pxesent invention relates also to polymer lattices of a homogeneous interpenetrated structure obtained by implementing the method previously described.
The invention will be further described by way of e~ample only wi-th reference to the accompanying drawings, in which:
Fig. 1 shows diagrammatically an interpenetrated structure of homogeneous na-ture of an epoxy lattice and of a polyester lattice.
Fig. 2 shows the main diagram of a microwave device which makes it possible to implement the method of -the present invention.
Fig. 3 shows the curves of the variations of a certain number of experimental parameters as a function o~ time during a polymerisation of a giYen mixture at a given power.
Fig. 4 shows the temperature variation curves (in degrees centi~rade), as a funcation of time, obtained Eor mixtures of variable composition and given power.
~ 5 --. ~.. ., ~
~ ~ .
~ 9 Fig. 5 sho~s the temperature varia-tion curves (in degrees centigrade) as a function of time, obtained on polymerisa-tion of a mixture of given composition and variable power; and Fig. 6 shows the curve of variation of the vetreous trans temperature of interpenetrated lattices as a function of the rate of polyester.
In the diagr~m of the device illustrated in Fig. 2 a micro~.~ave generator 1 delivers an electromagne-tic be~m polarised electrically with a fre~uency of ?c45 GHz and with a power Po between 0 and 1 Kw inclusive which is propogated within a wave guide according to the method of TEo1 includin~ a circulator 20 The beam then reaches the reactor 3 which consists of a cylind-rical pyrex receptacle with good transparency tomicrowaves, the reactor being filled with the mixture of the basic prepolymer constituen-ts.
Hence the initial beam can be divided in-to -three parts :
_ one part which is re1ected by -the reac-tor in the inlet wave guide and deviated through its circulator 2 or an equivalent ferrite system, towards a charge 4 which absorbs the radiations;
- one part is absorbed by the specimen taking into account the dieletric losses in the case of-microwaves of 2045 GHz9 the polarisable entities are the dipoles;
- one part is transmitted and absorbed by the second $~
charge 5.
The use of two char~es avoids stationary wav~
systems within the wave guide and it can be said that the waves are propagated in a progressive manner, The device as a whole consists~ ~oreover, of measuring and regulating systems that is, in ~ar-ticular a watt meter G, which measllres t,he variations of elec-tric power associated with -the different beams~
reflected and transmitted as well as the dielec-tric losses when the ~icro..aves pass through the specimen.
The temperature variations T of the speci~en treated by the ~icrow~ves are measured by means of an immersed thermistor insi~e a pyrex tube filled with silicone oil, which is transparen-t to electromagnetic radiations and which is itself partially immersed in the basic mix-ture ~hich is to be cross-linked. The variations of these different magni-tudes as a function of time are stored in a recording unit which is shown diagrammatically under the reference number 7.
By way of il.lustration some examples of preparation of polymer lattices of homogeneous interpenetrated structure in accord~nce ~rith the object of the ~resent invention will be sho~ belo~.
The basic prepolymer mixture examined below 25 consists of the following : ...
1 - Unsaturated polyester 70~' by t"~eight - styrene 30~' by weight - withou~ initiator.
f~
The manufacture of interpenetrated pol~ner la-ttices is usually carried ou-t by the conventional thermal method. This method of activating cross linking reactions of two polymers is tricky because ln order for it to be implemented in a satisfactory manner it involves reaction kine-tics which are similar. In fact, the final structure must be as homogeneous as ~ossible and especi~lly it mllst not inc]u~e islands or zones which are richer in one particular pol~ner, i.é. it is necessary to avoid the phenomenon of phase separation.
Such a result is di~ficult to achieve in practice, for the cross-l~king mechanisms of the t-~ro resins of the basic mixture are of a different -type in the large majority of cases, in such a manner as to avoid covalent chemical bridgings between the two lattices. Further-more, it is practically impossible in practice to makepolymerisation kinetics of the basic prepolymer con-sti-tuents coincide.
The s~lthesis of interpenetrated lattices is usually achieved by means of a thermal activation of the various cross-linking reactions, carried out in an oven or autoclave, and it is extremely rare to obtain homogeneous final structures owing to the difficulties encountered in ~akirl~ the cross-linking speeds coincide.
Usually structures ~!i th phase separa-tion are ob-tained.
This major drawback has~ moreover, considerably lirnited the development of interpenetrated polymer materials~
According to the method of the present invention, a microwave radiation is applied to the basic pre-polymer mixture : this microwave radiation is of a frequency spectrum chosen in order that it may inter~c-t preferentially with the first prepolymer and of a power intensity chosen i.n order that it may directly activate the exothermic cross-linking reaction Df the firs-t pre-polymer, whilst only trlggering the cross-linking of the second prepolymer under the combined acti.on of the heat due to the interaction of the microwave energy with the second prepolymer and the heat introduced by the cross-linking reaction of the first prepolymer, which make the combined prepagation o~ the two cross-linking reactions possible at similar speeds.
According -to ano~ther characteristic of the present invention, the two basic prepolymer cons-ti-tuents are cross-lir,ked according to differen-t polymerisation mechanisms~ In particular, one of the basic pre-polymers can be cross-linked according to a polymerisation mechanism which gives rise to free radicals, whilst the other basic prepolymer can be cross-linked according to a polymerisation mechanism by polycondensation.
I
The prepolymer which becomes cross-linked according to a polymerisation mechanism which gives rise -to free radicals can, for example, be formed with advantage by an unsaturated polyester resin9 especially by a solu-tion of 70% by weight unsaturated polyester resin in a solvent such as styrene1 The prepolymer of the basic mixture which is cross-linked according to a polymerisation mechanism by polycondensation can, for example, be formed to advantage by an epoxy resin, in particular of the type rG~`BA with the addition of a hardener such as diaminodipherylmethane.
Such a mixture of two basic prepolymer constituents can, for example be formed by approxirnately 20C~ by weight of a soltuion of unsatura-ted polyester resin and approximately 80% by weight of ar. epoxide resin with a hardener added.
According to one variant of the process of the present invention9the -two basic prepolymer consti-tuents can also be cross~ ed according to identical poly-merisati.on mechanisms in particular by polycon~ensation.
According to an addi.tional characteri.stic of -the method of preparation of the present invention, the mixture of at least two basi.c prepolymer constituents can, moreover, contain other additivesJ such as a reinforcing charge 9 in particular a mineral charge such as glass fibre.
The method which forms the object of the presen-t ~.3~'q~
invention can be implemented by using either a microwave treatment in a single mode cavity or in multi-mode cavity.
The frequency spectrum of the microwave radiation used, can, for example include frequencies between about 0O5 and about 100 G~z inclusive, pre:Eerably between about 1 and approximately ~GH7 inclusive, and in particular, a fre~uency of the order of 2.5 GHz.
The pxesent invention relates also to polymer lattices of a homogeneous interpenetrated structure obtained by implementing the method previously described.
The invention will be further described by way of e~ample only wi-th reference to the accompanying drawings, in which:
Fig. 1 shows diagrammatically an interpenetrated structure of homogeneous na-ture of an epoxy lattice and of a polyester lattice.
Fig. 2 shows the main diagram of a microwave device which makes it possible to implement the method of -the present invention.
Fig. 3 shows the curves of the variations of a certain number of experimental parameters as a function o~ time during a polymerisation of a giYen mixture at a given power.
Fig. 4 shows the temperature variation curves (in degrees centi~rade), as a funcation of time, obtained Eor mixtures of variable composition and given power.
~ 5 --. ~.. ., ~
~ ~ .
~ 9 Fig. 5 sho~s the temperature varia-tion curves (in degrees centigrade) as a function of time, obtained on polymerisa-tion of a mixture of given composition and variable power; and Fig. 6 shows the curve of variation of the vetreous trans temperature of interpenetrated lattices as a function of the rate of polyester.
In the diagr~m of the device illustrated in Fig. 2 a micro~.~ave generator 1 delivers an electromagne-tic be~m polarised electrically with a fre~uency of ?c45 GHz and with a power Po between 0 and 1 Kw inclusive which is propogated within a wave guide according to the method of TEo1 includin~ a circulator 20 The beam then reaches the reactor 3 which consists of a cylind-rical pyrex receptacle with good transparency tomicrowaves, the reactor being filled with the mixture of the basic prepolymer constituen-ts.
Hence the initial beam can be divided in-to -three parts :
_ one part which is re1ected by -the reac-tor in the inlet wave guide and deviated through its circulator 2 or an equivalent ferrite system, towards a charge 4 which absorbs the radiations;
- one part is absorbed by the specimen taking into account the dieletric losses in the case of-microwaves of 2045 GHz9 the polarisable entities are the dipoles;
- one part is transmitted and absorbed by the second $~
charge 5.
The use of two char~es avoids stationary wav~
systems within the wave guide and it can be said that the waves are propagated in a progressive manner, The device as a whole consists~ ~oreover, of measuring and regulating systems that is, in ~ar-ticular a watt meter G, which measllres t,he variations of elec-tric power associated with -the different beams~
reflected and transmitted as well as the dielec-tric losses when the ~icro..aves pass through the specimen.
The temperature variations T of the speci~en treated by the ~icrow~ves are measured by means of an immersed thermistor insi~e a pyrex tube filled with silicone oil, which is transparen-t to electromagnetic radiations and which is itself partially immersed in the basic mix-ture ~hich is to be cross-linked. The variations of these different magni-tudes as a function of time are stored in a recording unit which is shown diagrammatically under the reference number 7.
By way of il.lustration some examples of preparation of polymer lattices of homogeneous interpenetrated structure in accord~nce ~rith the object of the ~resent invention will be sho~ belo~.
The basic prepolymer mixture examined below 25 consists of the following : ...
1 - Unsaturated polyester 70~' by t"~eight - styrene 30~' by weight - withou~ initiator.
f~
2 - Epoxide resin of type D.G.E.B.A.
diamino diphenylinethane (hardener) The above mixture leads to a rigid interpenetrated polymer structure, that is -to say, vitreous, the two basic lattices bein~ themselves rigid.
It is however, pexfec-tly possible, within the framework of the present invention, -to s~art with other basic prepolymer mixtures leading individually to sof-t lattices, that is, elastic, or rigid. It is thus possible to associate between them two soft prepolymers or against a soft prepolymer with a rigid prepolymer.
It is observed that the nature of the cross-linking mechanisms is not fundamentally modified by the action of the microwave. For example, in the case o~ -the above mixture, the cross-linking mechanism of the unsaturated polyester resin in the presence of styrene is that of a polymerisation reaction, giving rise to free radicals and the mechanism of the cross-linking reaction of the epoxide resin in the presence of a hardener is -that of a polycondensation reaction.
On the other hand, -the method of the present in~ention introduces determini-tive advantages in relation to the method of activation by means of the conventional thermal method in the furnace or au-toclave; -the following are okserved in particular:
- a flexibility in the choice of the electric power of the microwave radiation which makes it possible -to ,~ .
bring the cross-linking kinetics of the two prepolymers together and -to avoid the drawback of phase separation;
- the possibility of stopping the microwave heating instantly in the case of the reactions running away;
- a more homogeneous structuring of the finished materials which in particular are baked righ-t through, unlike cross linking by thermal methods often observed owing to the penetration of the polymerisable medium by the electromagnetic waves.
The particular examples mentioned below have been achieved by implementation of a microwave trea-tment of a wave guide according to the method TE01 with a frequency of 2.45 GHz.
EX~MPLE 1 POLYMERISATION OF A GIVEN MIXTIJRE AT A GIVEN POWER
A weight of 20 g oE the basic mixture defined above was placed in a pyrex pill box. The experimental parame-ters are as follows:
Po: power of electromagnetic radiations delivered by the generator (unit watt) Po = 50W) Pu: power dissipated in the specimen by dielectric losses (unit: watt) T: average temperature of the specimen (unit C).
25 T' = dT/dt t: -time T': derivative of the -temperature in relation to time 'unit:
C/min;~
~, ~
~ 3~ ~
~ ., .
Pu' = dPu/dt Pu' : ~erivative of the ~ower in relation to time (unit watt/mill) The experimen-tal results are given in the form of the curves shown in Fig. 3~ The four curves shown correspond -to the follo~ling variations:
1. T - T (t) 2. Pu = Pu (t)
diamino diphenylinethane (hardener) The above mixture leads to a rigid interpenetrated polymer structure, that is -to say, vitreous, the two basic lattices bein~ themselves rigid.
It is however, pexfec-tly possible, within the framework of the present invention, -to s~art with other basic prepolymer mixtures leading individually to sof-t lattices, that is, elastic, or rigid. It is thus possible to associate between them two soft prepolymers or against a soft prepolymer with a rigid prepolymer.
It is observed that the nature of the cross-linking mechanisms is not fundamentally modified by the action of the microwave. For example, in the case o~ -the above mixture, the cross-linking mechanism of the unsaturated polyester resin in the presence of styrene is that of a polymerisation reaction, giving rise to free radicals and the mechanism of the cross-linking reaction of the epoxide resin in the presence of a hardener is -that of a polycondensation reaction.
On the other hand, -the method of the present in~ention introduces determini-tive advantages in relation to the method of activation by means of the conventional thermal method in the furnace or au-toclave; -the following are okserved in particular:
- a flexibility in the choice of the electric power of the microwave radiation which makes it possible -to ,~ .
bring the cross-linking kinetics of the two prepolymers together and -to avoid the drawback of phase separation;
- the possibility of stopping the microwave heating instantly in the case of the reactions running away;
- a more homogeneous structuring of the finished materials which in particular are baked righ-t through, unlike cross linking by thermal methods often observed owing to the penetration of the polymerisable medium by the electromagnetic waves.
The particular examples mentioned below have been achieved by implementation of a microwave trea-tment of a wave guide according to the method TE01 with a frequency of 2.45 GHz.
EX~MPLE 1 POLYMERISATION OF A GIVEN MIXTIJRE AT A GIVEN POWER
A weight of 20 g oE the basic mixture defined above was placed in a pyrex pill box. The experimental parame-ters are as follows:
Po: power of electromagnetic radiations delivered by the generator (unit watt) Po = 50W) Pu: power dissipated in the specimen by dielectric losses (unit: watt) T: average temperature of the specimen (unit C).
25 T' = dT/dt t: -time T': derivative of the -temperature in relation to time 'unit:
C/min;~
~, ~
~ 3~ ~
~ ., .
Pu' = dPu/dt Pu' : ~erivative of the ~ower in relation to time (unit watt/mill) The experimen-tal results are given in the form of the curves shown in Fig. 3~ The four curves shown correspond -to the follo~ling variations:
1. T - T (t) 2. Pu = Pu (t)
3. T' = Tt (t)
4. Pu' = Pu~ (t) In particular it is observed here that the temp-erature increases from 0C~ after having temporarily reached a value close to 50C corresponding -tv the fluxing transition of the mixture. When the temperature is sufficient, the cross-linking becomes in~tense 9 ~the -temperature increases and reaches a maximum (T : 147C) corresponding to an almost complete cross-linking.
The decrease observed beyond the maximum corresponds to the cooling of the cross-li~ed substance.
The power Pu increases progressively when the mixture becomes flui~ and soon passes through a maximum before the exothermy develops. The maximum corresponds to tle gelation of the reaction medium. The decrease which is subsequently observed corresponds -to the intensification of the bridging reactionsO When the material is completely cross-linked, Pu levels off.
The derived curves (3) and (4) ma~e it possi~le to define the particular points of integral curves T
and Pu better.
The i~itially pasty (or fluid) mixture is trans-ormed int,o a trans~arent soli~, which is vitreous and of yellow/orange colour.
AND GIVEN POWER (Po = 50 W) No. of tests 1 2 3 4 5 6 7 8 % epoxy 100 g5 90 80 60 40 20 0 ~,~ polyester 0 05 10 20 40 60 80 100 The experimental resul-ts are given in the attached Fig. 4.
In partlcular it is observed that the curves T-T
(t) of Fig. 4 have the same appearance wi-th exeeption of that of the nolyester (curve 8). ~rhen it is a question of mixtures the exothermy is triggered increas~
ingly later o the maximum is displaced towards the highest values of time when the polyester percentage is increased; -the latter, moreover, does not polymerise at the power Po used.
The other composi-tions (curves 1,2,3,4,5,6~7) regularly give rigid polymerised materials. It would be ex~ected that -the pure epoxide resin (test No. 'I) would lead to the most rapid exothexmy. But i-t is nothing of the sortO This tendency is associated with a physical state of the mixtures which are more mobile -and which therefore dissipate energy better - than the epoxide resin, EY~MPLE 3 POLYMERISATION OF A MIXTURE OF GIVEN COMPOSITION
~ND V M IABLE POWER (FIG. 5)0 Mix-ture: e~oxi~e 80% - Polyester 2~/o Powers Po: (1) 60 W - (2) 50 W - (~) 40 W
(4) ~0 W - (5) 20 W.
Without excluding the eventuali-ty o a specific microwave effect on the various reactions, the various curves are arranged in relation to one another in accordance with the hypothesis of a conversion of Pu into heat, that is, their exothermy is displaced towards the high values of -time when there is less heating (Po is reduced)~
It is useful in particular to note that Test No~ 1 (P = 60 W) leads to an opaque final structure, i.e.
it displays the phenomenon of phase separation due to too great a divergence be-tween the two kinetics of cross~ ing of the basic prepolymers. A reduction of the power Po was sufficient to cause this phenomenon to disappear and to lead to homogeneous materials.
~he cloudiness in fact disappears for Po ~ 40W.
VITREOUS TRANSITION TEMPERATURES T~ OF THE INTER-P~NETRATED NETWORKS ~FIG. 6).
The interpenetra-ted polymer networks are amorphous and rigid at ordinary temperatures ~or are in their vitreous state). They may be characterised by their vitreous -transition tempera-ture Tg. Fig. 6 shows the expected development of Tg as a function of -the poly-ester rate, this variation being characteristic of the interpenetra'ced lattices, for specimens prepared at
The decrease observed beyond the maximum corresponds to the cooling of the cross-li~ed substance.
The power Pu increases progressively when the mixture becomes flui~ and soon passes through a maximum before the exothermy develops. The maximum corresponds to tle gelation of the reaction medium. The decrease which is subsequently observed corresponds -to the intensification of the bridging reactionsO When the material is completely cross-linked, Pu levels off.
The derived curves (3) and (4) ma~e it possi~le to define the particular points of integral curves T
and Pu better.
The i~itially pasty (or fluid) mixture is trans-ormed int,o a trans~arent soli~, which is vitreous and of yellow/orange colour.
AND GIVEN POWER (Po = 50 W) No. of tests 1 2 3 4 5 6 7 8 % epoxy 100 g5 90 80 60 40 20 0 ~,~ polyester 0 05 10 20 40 60 80 100 The experimental resul-ts are given in the attached Fig. 4.
In partlcular it is observed that the curves T-T
(t) of Fig. 4 have the same appearance wi-th exeeption of that of the nolyester (curve 8). ~rhen it is a question of mixtures the exothermy is triggered increas~
ingly later o the maximum is displaced towards the highest values of time when the polyester percentage is increased; -the latter, moreover, does not polymerise at the power Po used.
The other composi-tions (curves 1,2,3,4,5,6~7) regularly give rigid polymerised materials. It would be ex~ected that -the pure epoxide resin (test No. 'I) would lead to the most rapid exothexmy. But i-t is nothing of the sortO This tendency is associated with a physical state of the mixtures which are more mobile -and which therefore dissipate energy better - than the epoxide resin, EY~MPLE 3 POLYMERISATION OF A MIXTURE OF GIVEN COMPOSITION
~ND V M IABLE POWER (FIG. 5)0 Mix-ture: e~oxi~e 80% - Polyester 2~/o Powers Po: (1) 60 W - (2) 50 W - (~) 40 W
(4) ~0 W - (5) 20 W.
Without excluding the eventuali-ty o a specific microwave effect on the various reactions, the various curves are arranged in relation to one another in accordance with the hypothesis of a conversion of Pu into heat, that is, their exothermy is displaced towards the high values of -time when there is less heating (Po is reduced)~
It is useful in particular to note that Test No~ 1 (P = 60 W) leads to an opaque final structure, i.e.
it displays the phenomenon of phase separation due to too great a divergence be-tween the two kinetics of cross~ ing of the basic prepolymers. A reduction of the power Po was sufficient to cause this phenomenon to disappear and to lead to homogeneous materials.
~he cloudiness in fact disappears for Po ~ 40W.
VITREOUS TRANSITION TEMPERATURES T~ OF THE INTER-P~NETRATED NETWORKS ~FIG. 6).
The interpenetra-ted polymer networks are amorphous and rigid at ordinary temperatures ~or are in their vitreous state). They may be characterised by their vitreous -transition tempera-ture Tg. Fig. 6 shows the expected development of Tg as a function of -the poly-ester rate, this variation being characteristic of the interpenetra'ced lattices, for specimens prepared at
5~ ~.
Note: The specimen at 100% polyester was prepared at po - 140 W, Of course the present invention does no-t need to be limited to the particular implementation ex,~mples described, but it is perfectly possible -to imagine a certain number of variations of execution. In.particular it is possible 'co implemen'c the method of the invention starting from basic mixtures containing more than two prepolymers, containing other monomers or again from basic mixtures in which one and/or the other prepolymer is replaced by a monomer. Moreover, the wave guide used can be replaced by multi-mode cavities~ tunnel furnaces or similar.
Note: The specimen at 100% polyester was prepared at po - 140 W, Of course the present invention does no-t need to be limited to the particular implementation ex,~mples described, but it is perfectly possible -to imagine a certain number of variations of execution. In.particular it is possible 'co implemen'c the method of the invention starting from basic mixtures containing more than two prepolymers, containing other monomers or again from basic mixtures in which one and/or the other prepolymer is replaced by a monomer. Moreover, the wave guide used can be replaced by multi-mode cavities~ tunnel furnaces or similar.
Claims (13)
1. Method of preparing polymer lattices of homogeneous interpenetrated structure starting from a mixture of at least two basic prepolymer constituents, wherein a microwave radiation is applied to the said mixture, the microwave radiation having a frequency spectrum chosen in order that it may preferentially interact with the first prepolymer and of a power intensity selected in order that it directly activates the exothermic cross-linking reaction of the first prepolymer, whilst only triggering the cross-linking of the second prepolymer under the combined action of the heat due to the interaction of the microwave energy with the second prepolymer and the heat introduced by the cross-linking reaction of the first prepolymer which makes possible the combined propagation of the two cross-linking reactions at similar speeds.
2. Method according to claim 1, wherein the two basic prepolymer constituents are cross-linked according to different polymerisation mechanisms.
3. Method according to claim 1, wherein one of the basic prepolymer constituents is cross-linked according to a free radical polymerisation mechanism and the other basic prepolymer constituent is cross-linked according to a polymerisation mechanism by polycondensation.
4. Method according to claim 3, wherein one of the basic prepolymer constituents is an unsaturated polyester resin and the other basic prepolymer constituent is an epoxide resin.
5. Method according to claim 41 wherein the mixture of the two prepolymer constituents comprises of a mixture of about 20% by weight of a solution of an unsaturated polyester resin in a styrene and of about 80% by weight of epoxide resin with a hardener added.
6. Method according to claim 1, wherein the two basic prepolymer constituents are cross-linked according to polymerisation mechanisms by polycondensation.
7. Method according to claim 1, wherein the mixture of at least two basic prepolymer constituents contains moreover other additives such as a reinforcing charge, in particular a mineral charge such as a charge of glass fibres.
8. Method according to claim 1, wherein a microwave treatment in a multimode cavity is used.
9. Method according to claim 1, wherein a microwave treatment in multimode cavity is used.
10. Method according to claim 1 wherein the frequency spectrum used comprises frequencies between about 0.5 and about 100 GHz inclusive.
11. Method according to claim 10 wherein the frequency spectrum used comprises frequencies between about 1 and approximately 5 GHz.
12. Method according to claim 11 wherein the frequency is of the order of 2.5 GHz.
13. Polymer lattices of homogeneous interpenetrated structure obtained by implementing the method accord-ing to claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8211279A FR2529215B1 (en) | 1982-06-28 | 1982-06-28 | PROCESS FOR THE PREPARATION OF POLYMER NETWORKS OF HOMOGENEOUS INTERPENETRATED STRUCTURE |
| FR8211279 | 1982-06-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189648A true CA1189648A (en) | 1985-06-25 |
Family
ID=9275465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000427439A Expired CA1189648A (en) | 1982-06-28 | 1983-05-04 | Method of preparing polymer lattices of homogeneous interpenetrated structure |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4468485A (en) |
| EP (1) | EP0101654B1 (en) |
| JP (1) | JPS598716A (en) |
| CA (1) | CA1189648A (en) |
| DE (1) | DE3361486D1 (en) |
| FR (1) | FR2529215B1 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2555188B1 (en) * | 1983-11-18 | 1986-10-31 | Electricite De France | METHOD FOR MANUFACTURING A COMPOSITE MATERIAL COMPRISING A CROSSLINKED POLYMERIC MATRIX AND FINELY DIVIDED ELECTRICALLY CONDUCTIVE CHARGES |
| FR2570646B1 (en) * | 1984-09-26 | 1987-10-30 | Pradom Ltd | PROCESS FOR THE PREPARATION OF COMPOSITE MATERIALS WITH ORIENTED REINFORCING ELEMENTS AND PRODUCTS OBTAINED |
| US4857244A (en) * | 1984-09-26 | 1989-08-15 | Pradom Limited | Process of making a composite product, especially a vehicle tire |
| EP0255561A1 (en) * | 1986-07-31 | 1988-02-10 | AEROSPATIALE Société Nationale Industrielle | Composite plastic containing a matrix based on polyepoxide-polyester interpenetrated network structure |
| FR2577169B1 (en) * | 1985-02-13 | 1987-06-12 | Aerospatiale | COMPOSITE MATERIAL COMPRISING A MATRIX OF INTERPENETRATED POLYMERIC NETWORKS |
| US5212234A (en) * | 1985-04-11 | 1993-05-18 | Dsm Resins B.V. | Moulding compound based on thermosetting resin material |
| NL8501059A (en) * | 1985-04-11 | 1986-11-03 | Dsm Resins Bv | PRESS COMPOSITION BASED ON THERMO-CURING RESIN MATERIAL. |
| US5210157A (en) * | 1989-08-15 | 1993-05-11 | Akzo N.V. | Interpenetrating network of ring-containing allyl polymers and epoxy resin, and a laminate prepared therefrom |
| ES2047244T3 (en) * | 1989-09-15 | 1994-02-16 | Akzo Nv | CHEMICALLY LINKED INTERPENETRATING RETICLE. |
| CA2086770A1 (en) * | 1992-01-10 | 1993-07-11 | Jyi-Faa Hwang | Epoxy interpenetrating polymer networks having internetwork bonds |
| JP3950241B2 (en) | 1997-10-17 | 2007-07-25 | 三菱重工業株式会社 | Resin composition, cured resin, and structure repair method, reinforcement method, repair material, reinforcement material |
| DE102007006776A1 (en) * | 2007-02-12 | 2008-08-21 | Dracowo Forschungs- Und Entwicklungs Gmbh | Polymer network with adjustable gel time and good mechanical and thermal properties, is obtained by mixing unsaturated polyester and natural epoxy resins |
| GB0716074D0 (en) * | 2007-08-17 | 2007-09-26 | Pipeline Induction Heat Ltd | Apparatus for coating pipes |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3252923A (en) * | 1962-04-18 | 1966-05-24 | Reichhold Chemicals Inc | Foamed polyester epoxide resin compositions and method of making same |
| US3463749A (en) * | 1967-08-17 | 1969-08-26 | David D Taft | Curable composition containing epoxy and vinyl modified polyester |
| DE1918053A1 (en) * | 1969-04-09 | 1970-10-29 | Papierfabrik Gmbh | Solvent-free liquid binder curable at high - temps |
| CH557848A (en) * | 1970-10-30 | 1975-01-15 | Quaker Oats Co | SYNTHETIC RESIN MIXTURE WITH MUTUAL-PENETATING POLYMER NETWORKS. |
| US4302553A (en) * | 1970-10-30 | 1981-11-24 | Harry L. Frisch | Interpenetrating polymeric networks |
| GB1360910A (en) * | 1971-02-10 | 1974-07-24 | Showa Highpolymer | Resinous composition |
| US3926889A (en) * | 1971-06-14 | 1975-12-16 | Borden Inc | Preparation of plasticized latexes using high-density vibrational energy |
| JPS5218799A (en) * | 1975-08-04 | 1977-02-12 | Agency Of Ind Science & Technol | Composition of adhesive base used in water |
| US4011197A (en) * | 1975-09-18 | 1977-03-08 | Dow Corning Corporation | Method of curing organosiloxane compositions using microwaves |
| US4129488A (en) * | 1976-11-08 | 1978-12-12 | Scm Corporation | Ultraviolet curable epoxy-polyester powder paints |
| US4243744A (en) * | 1978-12-22 | 1981-01-06 | Exxon Research & Engineering Co. | Microwave curing of photoresist films |
| DE2916929A1 (en) * | 1979-04-26 | 1980-11-06 | Bosch Gmbh Robert | METHOD FOR CURING REACTION RESIN |
| US4360607A (en) * | 1979-09-04 | 1982-11-23 | Phillips Petroleum Company | Microwave energy sensitizing concentrate |
-
1982
- 1982-06-28 FR FR8211279A patent/FR2529215B1/en not_active Expired
-
1983
- 1983-01-11 US US06/457,133 patent/US4468485A/en not_active Expired - Fee Related
- 1983-04-30 JP JP58077364A patent/JPS598716A/en active Pending
- 1983-05-04 CA CA000427439A patent/CA1189648A/en not_active Expired
- 1983-06-16 EP EP83401245A patent/EP0101654B1/en not_active Expired
- 1983-06-16 DE DE8383401245T patent/DE3361486D1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4468485A (en) | 1984-08-28 |
| FR2529215A1 (en) | 1983-12-30 |
| EP0101654A1 (en) | 1984-02-29 |
| FR2529215B1 (en) | 1987-05-07 |
| EP0101654B1 (en) | 1985-12-11 |
| DE3361486D1 (en) | 1986-01-23 |
| JPS598716A (en) | 1984-01-18 |
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