Phase transitions of polymers over T and P ranges under various hydraulic fluids: Polymer/supercritical gas systems and liquid to solid polymer transitions

This article was presented at the 4th International Conference on Polymer Behavior, International Union of Pure and Applied Chemistry, Lodz, Poland, September 20-23, 2010.International audienceThe use of three different calorimeters made it possible to measure the overall kinetics of isotactic polypropylene in the α-phase in a wide temperature range. Original results concerning the growth rate of α spherulites were also obtained by optical microscopy by using a prototype hot stage developed in our laboratory. A new growth regime seems to exist at low crystallization temperature. The number of nuclei shows a smooth evolution with temperature with no rupture in the nucleation behavior in the low-temperature range. Combination of experimental results and an appropriate extrapolation procedure lead to an overall kinetics law valid in the whole domain of existence of the α-phase. This law is based on Ozawa's formalism. It will be used in polymer processing

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Crystallization of polypropylene at high cooling rates: Microscopic and calorimetric studies

Boyer

Robinson

Ganet

et al. 2012

J of Applied Polymer Sci

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The role of nucleating agents in high-pressure-induced gamma crystallization in isotactic polypropylene

et al. 2014

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Nucleation of the γ-form in isotactic polypropylene (PP) under high pressure was investigated. Three nucleating agents were used to nucleate crystallization of PP under atmospheric pressure: commercial Hyperform HPN-20E from Milliken Chemical, poly(tetrafluoroethylene) particles nucleating the α-form, and calcium pimelate nucleating the β-form. Crystallization of neat PP and PP with addition of 0.2 wt% of the nucleating agents was studied. Specimens were either kept at 200 °C under pressure of 200 MPa for time ranging from 2 min to 4 h or for 15 min under pressure ranging from 1.3 to 300 MPa. After cooling to ambient temperature and releasing the pressure, the specimens were analyzed by DSC, WAXD, and PLM to have an insight into the structure and to determine a crystallinity level and contents of crystallographic forms. Both α-nucleating agents strongly nucleated crystallization of PP under high pressure in the γ-form, whereas the β-nucleating agent had only a slight effect. The results show the possibility to use nucleating agents to nucleate the γ-form of PP under high pressure.

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In Memoriam: Jean-Pierre E. Grolier (1936–2022)

Wilhelm

2022

J Solution Chem

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Phase transitions of polymers over T and P ranges under various hydraulic fluids: Polymer/supercritical gas systems and liquid to solid polymer transitions

Cited by 8 publications

References 45 publications

Crystallization of polypropylene at high cooling rates: Microscopic and calorimetric studies

Crystallization of polypropylene at high cooling rates: Microscopic and calorimetric studies

The role of nucleating agents in high-pressure-induced gamma crystallization in isotactic polypropylene

In Memoriam: Jean-Pierre E. Grolier (1936–2022)

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