Effects of polydispersity index and molecular weight on crystallization kinetics of syndiotactic polystyrene (sPS)

Chen, Chen-Ming; Hsieh, Tsung−Eong; Ju, Ming-Yih

doi:10.1016/j.jallcom.2009.02.003

Cited by 10 publications

(10 citation statements)

References 13 publications

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“…At the same T c value, the t 0.5 values are smaller in PHES12k than in PHES58k, indicating that PHES12k crystallizes faster than PHES58k under the same crystallization conditions. Similar trends were also found for PEA and sPS with low and high molecular weights. , …”

Section: Resultssupporting

confidence: 80%

“…It is well-known that the crystallization kinetics and morphology of semicrystalline polymers are affected by many factors, such as crystallization temperature, crystallization time, nucleating agent, molecular weight, etc. It should be noted that, unitl now, the effect of molecular weight on the crystallization kinetics of polymers has not received much attention. − Jenkins et al studied the effect of molecular weight on the crystallization kinetics of polycaprolactone (PCL), and they found that both the degree of crystallinity and the primary composite rate constant of PCL decreased with increasing molecular weight . Okui et al studied the molecular weight dependence of the linear crystal growth rate of PES in a wide range of crystallization temperature, and they found that the maximum growth rate first increased with molecular weight, up to 3000 g/mol, and then decreased .…”

Section: Introductionmentioning

confidence: 99%

“…They found that low-molecular-weight PEA crystallized faster than high-molecular-weight PEA under the same crystallization conditions; moreover, the crystal structures were the same, despite the molecular weight . Hsieh et al studied the effects of molecular weight and polydispersity index on the isothermal crystallization kinetics of syndiotactic polystyrene (sPS) . They found that both the overall crystallization rate and spherulite growth rate of sPS depended on the crystallization temperatures, molecular weight, and polydispersity index; moreover, the crystallization rate of sPS increased as the molecular weight and polydispersity index each decreased …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crystallization Kinetics and Morphology of Novel Biodegradable Poly(hexamethylene succinate-co-3 mol % ethylene succinate) with Low and High Molecular Weights

Yang

Qiu

2013

Ind. Eng. Chem. Res.

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The crystal structure, basic thermal behavior, nonisothermal melt crystallization behavior, overall isothermal melt crystallization kinetics, and spherulitic morphology of novel biodegradable poly(hexamethylene succinate-co-3 mol % ethylene succinate) P(HS-co-3 mol %ES) with low and high molecular weights, i.e., PHES12k and PHES58k were investigated. Both PHES12k and PHES58k have the same crystal structure as neat poly(hexamethylene succinate). The glass-transition temperatures are almost the same for both PHES12k and PHES58k. The melt point temperatures and crystallization peak temperatures are higher in PHES12k than in PHES58k; however, the equilibrium melting point temperatures are lower in PHES12k than in PHES58k. With an increase in crystallization temperature, the overall isothermal melt crystallization rates decrease gradually for both PHES12k and PHES58k; moreover, at the same crystallization temperature, PHES12k crystallizes faster than PHES58k. The spherulitic growth rates are faster in PHES12k than in PHES58k, while the nucleation densityof the spherulites is lower in PHES12k than in PHES58k.

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Section: Resultssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Crystallization Kinetics and Morphology of Novel Biodegradable Poly(hexamethylene succinate-co-3 mol % ethylene succinate) with Low and High Molecular Weights

Yang

Qiu

2013

Ind. Eng. Chem. Res.

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“…For a polymer with broad molecular weight distribution, the PDI is much higher than 1. The PDI is known to be an important parameter for micro-phase separation of a mixture of heterogeneous polymer [8], as well as for crystallization kinetics [9].…”

Section: Introductionmentioning

confidence: 99%

Effect of molecular weight distribution on e-beam exposure properties of polystyrene

Dey

Cui

2013

Nanotechnology

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Polystyrene is a negative electron beam resist whose exposure properties can be tuned simply by using different molecular weights (Mw). Most previous studies have used monodisperse polystyrene with a polydispersity index (PDI) of less than 1.1 in order to avoid any uncertainties. Here we show that despite the fact that polystyrene's sensitivity is inversely proportional to its Mw, no noticeable effect of very broad molecular weight distribution on sensitivity, contrast and achievable resolution is observed. It is thus unnecessary to use the costly monodisperse polystyrene for electron beam lithography. Since the polydispersity is unknown for general purpose polystyrene, we simulated a high PDI polystyrene by mixing in a 1:1 weight ratio two polystyrene samples with Mw of 170 and 900 kg mol(-1) for the high Mw range, and 2.5 and 13 kg mol(-1) for the low Mw range. The exposure property of the mixture resembles that of a monodisperse polystyrene with similar number averaged molecular weight Mn, which indicates that it is Mn rather than Mw (weight averaged molecular weight) that dominates the exposure properties of polystyrene resist. This also implies that polystyrene of a certain molecular weight can be simulated by a mixture of two polystyrenes having different molecular weights.

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“…This might stem from tiny amounts of atactic polystyrene ( at -PS) in the st -PS produced by Ti-3 . at -PS is miscible with st -PS [ 37 ], has a much lower T g than st -PS, and consequently reduces the overall T g value [ 38 ].…”

Section: Resultsmentioning

confidence: 99%

Homopolymerization of Ethylene, 1-Hexene, Styrene and Copolymerization of Styrene With 1,3-Cyclohexadiene Using (h5-Tetramethylcyclopentadienyl)dimethylsilyl(N-Ar’)amido-TiCl2/MAO (Ar’=6-(2-(Diethylboryl)phenyl)pyrid-2-yl, Biphen-3-yl)

et al. 2011

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The propensity of a half-sandwich (η5-tetramethylcyclopentadienyl)dimethylsilylamido TiIV-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclo-hexadiene is described. The reactivity of Ti-8 was investigated in comparison to a 6-(2-(diethylboryl)phenyl)pyrid-2-yl-free analogue (Ti-3).

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Effects of polydispersity index and molecular weight on crystallization kinetics of syndiotactic polystyrene (sPS)

Cited by 10 publications

References 13 publications

Crystallization Kinetics and Morphology of Novel Biodegradable Poly(hexamethylene succinate-co-3 mol % ethylene succinate) with Low and High Molecular Weights

Crystallization Kinetics and Morphology of Novel Biodegradable Poly(hexamethylene succinate-co-3 mol % ethylene succinate) with Low and High Molecular Weights

Effect of molecular weight distribution on e-beam exposure properties of polystyrene

Homopolymerization of Ethylene, 1-Hexene, Styrene and Copolymerization of Styrene With 1,3-Cyclohexadiene Using (h5-Tetramethylcyclopentadienyl)dimethylsilyl(N-Ar’)amido-TiCl2/MAO (Ar’=6-(2-(Diethylboryl)phenyl)pyrid-2-yl, Biphen-3-yl)

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