Blends of polycarbonate and acrylic polymers: Crystallization of polycarbonate

Debier, D.; Jonas, Alain M.; Legras, Roger

doi:10.1002/(sici)1099-0488(19980915)36:12<2197::aid-polb17>3.3.co;2-7

Cited by 12 publications

(16 citation statements)

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“…No clear boundaries separated the radiating lamellae of the small spherulites from the unorganized granular lamellae of the nonspherulitic regions. A resemblance to morphological features described by Keith and Padden29–31 and others32–36 suggested that less‐crystallizable PEI blocks were rejected from the crystals into the interlamellar regions. Although the possibility existed that the PET unit cell accommodated PEI blocks to some extent, the compelling morphological observations indicated that the PEI blocks were mainly rejected from the crystals.…”

Section: Resultsmentioning

confidence: 56%

Improving oxygen barrier properties of poly(ethylene terephthalate) by incorporating isophthalate. II. Effect of crystallization

Hiltner

Baer

2005

J of Applied Polymer Sci

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ABSTRACT:The present study examined crystallization of poly(ethylene terephthalate) (PET) and a series of random and blocky copolymers in which up to 30% of the terephthalate was replaced with isophthalate. Isothermal crystallization kinetics and direct observation of the spherulitic morphology revealed that the blocky copolymers crystallized more rapidly than PET, at least in part, as the result of enhanced spherulite nucleation. The statistical copolymers with 10 and 20% isophthalate achieved almost the same level of crystallinity as that of the blocky copolymers. The statistical copolymers with 10% isophthalate crystallized almost as fast as PET, although the statistical copolymer with 20% isophthalate crystallized much more slowly. Crystallization substantially reduced the oxygen permeability. Analysis of oxygen-transport parameters in terms of a two-phase structural model that considered a dispersion of lower-permeability spherulites in an amorphous matrix of higher permeability revealed that dedensification of the PET interlamellar amorphous regions was responsible for the unexpectedly high oxygen solubility of crystallized PET. In contrast, copolymerization with isophthalate prevented dedensification of the interlamellar amorphous regions. As a result, crystallization was more effective in reducing the oxygen permeability. It was speculated that segregation of kinked isophthalate units to the amorphous regions of the spherulite relieved constraint on the interlamellar amorphous chain segments.

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Section: Resultsmentioning

confidence: 56%

Improving oxygen barrier properties of poly(ethylene terephthalate) by incorporating isophthalate. II. Effect of crystallization

Hiltner

Baer

2005

J of Applied Polymer Sci

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“…This discrepancy might be associated with the difficulty in determining the precise aPS diffusivity, despite the fact that the intermolecular interaction between the sPS and aPS components is absent in our blends. Other factors, such as the stiffness of the crystallizable chains and the lamellar growth process, have been suggested to ultimately define the blend morphology 36. These observations lead us to conclude that the δ parameter is to be considered a qualitative expression for the segregation mode unless a precise mutual diffusivity of the diluents is provided.…”

Section: Resultsmentioning

confidence: 96%

Crystallization, Melting and Morphology of Syndiotactic/Atactic Polystyrene Blends: Molecular Weight Effects of Atactic Polystyrene

Wang¹,

Wang²,

Fan³

2005

Macro Chemistry & Physics

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Summary: Molecular weight (MW) effects of atactic polystyrene (aPS) on the morphologies and crystallization kinetics of syndiotactic polystyrene (sPS) blends have been investigated, and miscibility was confirmed for all the sPS/aPS blends. Addition of aPS(M) or aPS(L) leads to a significant increase in the entropy of mixing and gives rise to a pronounced decrease in the equilibrium melting temperature of the blends. On heating from the glassy state, the crystallization peak temperature of the sPS/aPS(H) blend increased with increasing aPS content due to a dilution effect, whereas those of sPS/aPS(M) and sPS/aPS(L) decreased mainly due to enhanced chain mobility. On cooling from the melt state, the crystallization peak temperature decreased with increasing aPS content regardless of the aPS MW. A higher activation energy is required for the sPS component transport from the miscible melt to the growth front in the sPS/aPS(L), suggesting that extra energy is required for the demixing process. Interspherulitic segregation of aPS diluents was evident in the sPS/aPS(L) blends, while interfibrillar segregation morphology was obtained in the sPS/aPS(H) as well as the sPS/aPS(U) blends.

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“…PC is categorized as amorphous polymer because of its extremely slow crystallization without additives. Thus, the crystallization of PC has been mostly studied in the presence of low‐molecular‐weight organic components to promote the mobility of PC chains during the last three decades 1,2. Very few publications have addressed the crystallization of pure PC from the bulk at different annealing temperatures.…”

Section: Introductionmentioning

confidence: 99%

Polycarbonate Crystallization by Vapor‐Grown Carbon Fiber with and without Magnetic Field

Takahashi

Yonetake

Koyama

et al. 2003

Macromol. Rapid Commun.

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Polycarbonate (PC)/vapor‐grown carbon fiber (VGCF™) composite was prepared through melt compounding. It was unexpectedly found from differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD) that the crystallization of PC was substantially accelerated in the presence of the ordered graphite surface of VGCF™. To make an aligned structure of PC crystallization together with the orientation of VGCF™, a magnetic field of 2.4 T was applied to the composite under several temperature profiles. The WAXD pattern revealed that not only dispersed VGCF™ but also matrix PC crystallization was magnetically aligned through the optimization of processes. The evidence for PC crystallization by VGCF™ with and without magnetic force is described.

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Blends of polycarbonate and acrylic polymers: Crystallization of polycarbonate

Cited by 12 publications

References 0 publications

Improving oxygen barrier properties of poly(ethylene terephthalate) by incorporating isophthalate. II. Effect of crystallization

Improving oxygen barrier properties of poly(ethylene terephthalate) by incorporating isophthalate. II. Effect of crystallization

Crystallization, Melting and Morphology of Syndiotactic/Atactic Polystyrene Blends: Molecular Weight Effects of Atactic Polystyrene

Polycarbonate Crystallization by Vapor‐Grown Carbon Fiber with and without Magnetic Field

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