Phase homogenization of mixtures of poly(m-xylene adipamide) and nylon 6 by interchange reactions

Takeda, Y.; Paul, Donald R

doi:10.1016/0032-3861(91)90107-t

Cited by 47 publications

(28 citation statements)

References 33 publications

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“…Indeed, polymer blending is an attractive alternative to produce new polymeric materials with desirable properties without having to undertake the synthesis of totally new compounds. Binary blends of both crystallizable polymers are usually believed to be immiscible; however, partial miscibility can arise if the chemical structure of the components is very similar [9][10][11] and if they exhibit polar or specific intermolecular interactions. Ester-interchange reactions often take place during melt processing of polyester-polyester blends, thus improving miscibility or compatibility.…”

Section: Introductionmentioning

confidence: 99%

Reactive Blending of Aromatic Polyesters: Thermal Behaviour of Co‐precipitated Mixtures PTT/PET

Castellano

Turturro

Valenti

et al. 2006

Macro Chemistry & Physics

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Summary: Due to its unique combination of properties, PTT is a promising material for textile fibre and engineering thermoplastic applications, both as neat polymer and in formulated products. To bring down the cost yet keeping some of its advantageous properties it seems interesting to apply PTT in blends and particularly with PET. We consider here the effect of composition and reaction time on co‐precipitated mixtures PTT/PET, in terms of melting and crystallization behaviour, solution properties and morphology. Blends of various compositions were prepared from mixed solutions, kept in the DSC at 280 °C for different times (0–120 min) and analysed during a successive cooling‐heating cycle. A single Tg was detected for each composition, indicative of miscibility in the glassy state. Melting temperatures, at fixed composition, decrease with increasing treatment time. Mixtures rich in one component show a single Tm, whereas two distinct peaks were observed for the 50/50 blend; on increasing the treatment time some transesterification takes place, evidenced by the melting peak broadening and merging together. The overall crystallinity developed when transesterification plays a role strongly depends on composition: it is inhibited for the 50/50 mixture on cooling, though it can be induced to some extent by reheating or holding during cooling, whereas in one component‐rich blends the main effect is a reduction of the crystallization temperature. Isothermal crystallizations were also carried out as a function of the composition and of the residence time in the molten state; crystallization rate decreases with increasing holding time in the melt. Morphology of PTT and PTT‐rich mixtures under the adopted crystallization conditions exhibits typical banded spherulites, whose growth rate and band spacing vary with melt holding time; moreover, less regular concentric circles develop on increasing residence time at 280 °C.Spherulitic texture developed at 198 °C after 60 min storage at 280 °C by a PTT/PET 90/10 mixture.magnified imageSpherulitic texture developed at 198 °C after 60 min storage at 280 °C by a PTT/PET 90/10 mixture.

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Section: Introductionmentioning

confidence: 99%

Reactive Blending of Aromatic Polyesters: Thermal Behaviour of Co‐precipitated Mixtures PTT/PET

Castellano

Turturro

Valenti

et al. 2006

Macro Chemistry & Physics

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“…Takeda and Paul [92] studied blends of poly(m-xylene adipamide) and nylon 6 prepared by extrusion at 260°C (opaque, two glass transitions) and 29OOC (transparent, single glass transition). Phase homogenisation was the result of interchange reactions, as shown by thermal, dynamic mechanical, and NMR analyses.…”

Section: Polyamide/polyamide Blendsmentioning

confidence: 99%

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

Xanthos¹,

Warth²

1999

Transreactions in Condensation Polymers

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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...

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“…It is known that at temperatures of about 250°C, copolymer formation occurs by amide exchange in a melt of two polyamides [176,180]. Some attempts have been made to characterise the extent of interchange reactions in mixtures of poly(m-xylene adipamide) and Nylon 6 [181] and also in mixtures of Nylon-z, y polymers [182], where x indicates the number of carbon atoms separating the nitrogen atoms in the diamine and y the number of straight-chain carbon atoms in the dibasic acid. However, these analyses by NMR are not sufficiently convincing.…”

Section: Reactions Taking Place In Polyamides Involving Amine Andmentioning

confidence: 99%

Interchange Reactions in Condensation Polymers and Their Analysis by NMR Spectroscopy

Kricheldorf¹,

Denchev²

1999

Transreactions in Condensation Polymers

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Phase homogenization of mixtures of poly(m-xylene adipamide) and nylon 6 by interchange reactions

Cited by 47 publications

References 33 publications

Reactive Blending of Aromatic Polyesters: Thermal Behaviour of Co‐precipitated Mixtures PTT/PET

Reactive Blending of Aromatic Polyesters: Thermal Behaviour of Co‐precipitated Mixtures PTT/PET

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

Interchange Reactions in Condensation Polymers and Their Analysis by NMR Spectroscopy

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