Sequential reordering in condensation copolymers, 4. Crystallization-induced sequential reordering in poly(ethylene terephthalate)/polycarbonate copolymers as revealed by the behavior of the amorphous phases

Denchev, Z.; Sarkissova, Marianna; Radusch, Hans‐Joachim; Luepke, Thomas; Fakirov, S.

doi:10.1002/(sici)1521-3935(19980201)199:2<215::aid-macp215>3.0.co;2-t

Cited by 20 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This leads to a lower degree of crystallinity at usual under cooling for the finest degree of dispersion and complex melting patterns in DSC 44. This could explain the dual crystallization exotherms observed during the dynamic crystallization from the melt of blends with a high content of PC (typically more than 60%) reported by Reinsch et al45 The authors attributed the normal exotherm at roughly 210 °C to normal PET crystallization while the low temperature exotherm was attributed to a co‐crystalline form of PET‐PC or a different crystalline structure.…”

Section: Introductionmentioning

confidence: 94%

See 1 more Smart Citation

Immiscible Blends of PC and PET, Current Knowledge and New Results: Rheological Properties

Carrot

Mbarek

Jaziri

et al. 2007

Macro Materials & Eng

View full text Add to dashboard Cite

This paper deals with immiscible blends of poly(ethylene terephthalate) obtained by melt blending with polycarbonate. A large survey of the current knowledge in the field of these blends is presented. Resolved and unresolved issues concerning the effect of exchange reactions on the miscibility of the components are addressed. The experimental part of the paper focuses on the rheological behavior of PET/PC blends. Blends containing various polymer ratios were obtained by melt blending with and without transesterification catalysts. Oscillatory shear flow in the melt was used to characterize the rheology of the various samples. A plot of the oscillatory data, similar to the Van Gurp Palmen plot, is used to point out the broadening of the co‐continuity window when in situ compatibilization takes place.magnified image

show abstract

Section: Introductionmentioning

confidence: 94%

“…Finally, though long residence times in the melt give rise to exchange reaction and generate block copolymers of PET and PC, followed by a randomization, restoring of block copolymers from truly amorphous random PET‐PC copolymers by annealing at 235 °C, called crystallization induced sequential reordering, have been mentioned 45…”

Section: Introductionmentioning

confidence: 99%

Immiscible Blends of PC and PET, Current Knowledge and New Results: Rheological Properties

Carrot

Mbarek

Jaziri

et al. 2007

Macro Materials & Eng

View full text Add to dashboard Cite

show abstract

“…With the PET/PC system, the DSC method and instrumentation used allowed us to follow the behaviour of the amorphous phases as a function of the crystallinity changes only in the blend compositions with predominant concentrations of the non-crystallisable component (Figure 11A). Therefore, the changes in Tg values with the progress of transreactions in the PET/PC system were followed, using a more sensitive technique (DMTA), in order to get further evidence for the direction of these transreactions in the system under investigation [80]. Therefore, the changes in Tg values with the progress of transreactions in the PET/PC system were followed, using a more sensitive technique (DMTA), in order to get further evidence for the direction of these transreactions in the system under investigation [80].…”

Section: Evidence Of Crystallisation-induced Reorderkg Derived Fiommentioning

confidence: 99%

“…Temperature dependences of the loss modulus El' (in bending mode) for neat homopolymers, their equimolar mixture, and copolymers with different sequential order: (a) neat PET; (b) neat PC; (c) mechanical mixture; (d) block copolymer;(e) randomised sample; (f) restored block copolymer[80] …”

mentioning

confidence: 99%

“…Dependences of viscosity q* on frequency at 280°C of homopolymers, their equimolar mixture, and copolymers with different sequential order: (a) neat PET; (b) neat PC; (c) mechanical mixture; (d) block copolymer; (e) randomised sample; (f) restored block copolymer[80] Dependences of viscosity q* on frequency at 280°C of homopolymers, their equimolar mixture, and copolymers with different sequential order: (a) neat PET; (b) neat PC; (c) mechanical mixture; (d) block copolymer; (e) randomised sample; (f) restored block copolymer[80] …”

mentioning

confidence: 99%

See 1 more Smart Citation

Sequential Reordering in Condensation Copolymers

Fakirov¹,

Denchev²

1999

Transreactions in Condensation Polymers

View full text Add to dashboard Cite

Evidence of the occurrence of chemical interactions in blends of condensation polymersDuring recent decades, polymer blends have become of prime commercial importance [l]. Currently, they constitute over 30% of the polymer market. The blends of condensation polymers are of particular interest because of their unique ability to undergo interchange reactions (additional condensation and transreactions, called also exchange reactions or mid-chain reactions) [2]. The latter are reversible and can be performed either in the molten [2] or in the solid state (31 under appropriate conditions. Elevated temperatures between 180°C and 300°C and addition of catalysts are among the basic requirements in this respect. Although the study of transreactions started 50 years ago with the pioneer work of Flory [4], even now some details of the process are not completely understood. There is no common consent in the literature on the relative importance of the three possible mechanismsalcoholysis, acidolysis or direct ester exchange [5-121.Interchain reactions take place whenever the conditions required (appropriate temperatures and chemical compositions) are available. They occur in homopolycondensates, as can be concluded from the upgrading of molecular weight due to additional condensation; transactions have been convincingly confirmed by studying blends of protonated poly(ethy1ene terephthalate) (PET) with deuterium-labelled ( d 4 ) PET by small-angle neutron scat- Transreactions in Condensation PolymersStoyho Fahirov copyright 0 WILEY-VCH Verlag GrnbH. 1999 Evidence derived fmm the behaviour of crystalline and amor- IR study and weight control after selective extractionThe DSC and WAXS measurements described in Section 1.2 were performed with annealed PET/PA 6 blends without any further treatment. The same samples were also studied by IR spectroscopy after application of selective extraction, accompanied by weight control of the fractions. This phases phous phases

show abstract

Effects of Transreactions on the Compatibility and Miscibility of Blends of Condensation Polymers

Xanthos¹,

Warth²

1999

Transreactions in Condensation Polymers

View full text Add to dashboard Cite

Principles of blend compatibilisationFew polymers form truly miscible blends characterised by a single glass transition temperature (Tg) and homogeneity on a 5-10nm scale with domain sizes comparable to the dimension of a macromolecular statistical segment. The majority of blends are immiscible, i e . , possess a phase separated morphology. Blends of this type are often preferred over the miscible ones since they combine some of the important characteristics of both blend constituents. Blend composition, viscoelastic properties of the components, and interfacial adhesion are among the parameters known to control the size and morphology of the dispersed phase and its stability to coalescence. Heterogeneous blends of technological importance are termed "compatible" and they constitute the majority of the commercial blends introduced in the past 30 years. In such blends, often known also as alloys, satisfactory physical and mechanical properties are related to the presence of an interphase modified through compatibilisation and the formation of a fine dispersed morphology resistant to phase separation.Polymer compatibility, which may lead ultimately to complete thermodynamic miscibility, may be enhanced by various methods. In addition to cocrystallisation and cocrosslinking, strong interactions such as acidbase or ion-dipole, hydrogen bonding and transition metal complexation Transreactions in Condensation PolymersStoyho Fahirov copyright 0 WILEY-VCH Verlag GrnbH. 1999 412 M. Xanthos, H. Warth between suitably functionalised components, have been shown to improve compatibility. More commonly, compatibility is promoted through interfacially active copolymers (e.g., block, graft, random) with segments capable of specific interactions and/or chemical reactions with the blend components. The copolymers may be added separately, or formed in situ through chemical reactions, often catalysed by the addition of low molecular weight (MW) compounds. Reactive and non-reactive compatibilisation of polymer blends has been the subject of numerous reviews [l-71.During blending of a pair of suitably functionalised polymers A and B, interchain block, graft, or random copolymers may be formed at various concentrations through covalent or ionic bonding. According to Brown [3] , the following are five general types of chemical processes/reactions by which interchain copolymer formation has been achieved in extruder reactors: 1. Chain cleavage/recombination (main chain of A/main chain of B or 2. End-group of A/end-group of B; block. 3. End-group of A/pendant functionality of B; graft. 4. Covalent cross-linking: pendant functionality of Alpendant functionality of B or main chain of A/main chain of B; graft (crosslinked network). Ionic bond formation between A and B; usually graft (usually crosslinked).The compatibilisers formed in situ have segments that are chemically identical to those in the respective unreacted homopolymers and are thought to be located preferentially at the interface, thus lowering interfacial tension, and also promo...

show abstract

Sequential reordering in condensation copolymers, 4. Crystallization-induced sequential reordering in poly(ethylene terephthalate)/polycarbonate copolymers as revealed by the behavior of the amorphous phases

Cited by 20 publications

References 0 publications

Immiscible Blends of PC and PET, Current Knowledge and New Results: Rheological Properties

Immiscible Blends of PC and PET, Current Knowledge and New Results: Rheological Properties

Sequential Reordering in Condensation Copolymers

Effects of Transreactions on the Compatibility and Miscibility of Blends of Condensation Polymers

Contact Info

Product

Resources

About