Fast cooling of (non)-nucleated virgin and recycled poly(propylenes): Effect of processing conditions on structural and mechanical properties

Abstract

. Fast cooling of (non)-nucleated virgin and recycled poly(propylenes) : effect of processing conditions on structural and mechanical properties. Thermochimica Acta, 603, 94-102. DOI: 10.1016/j.tca.2014 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. A B S T R A C TIn this study, the effect of processing parameters, i.e., the cooling rate and pressure, on the structureproperty relationships for nucleated and non-nucleated i-PP from virgin and recycled sources was investigated. Special attention was given to the brittle-to-ductile transition of nucleated i-PP from plastic packaging waste. Differential fast scanning calorimetry and dilatometry were used to mimic industrial process conditions. From the calorimetric experiments, it was observed that under ambient pressure the mesomorphic phase was formed upon fast cooling, which was confirmed by WAXD analysis. The dilatometry results showed that by applying pressure also g-phase crystals are formed. Nucleated samples showed an increased tendency for the g-phase formation and a decreased tendency for mesomorphic phase formation. Up to now, recycled i-PP showed a brittle behavior, but this study showed that by applying a sufficiently high cooling rate, the yield stress can be reduced and a stabilization of the deformation can be obtained leading to a ductile behavior for recycled i-PP.

Cooling rate dependence of the crystallinity at nonisothermal crystallization of polymers: A phenomenological model

“…[1][2][3] The investigation and simulation of polymer crystallization during cooling is an ongoing task in polymer science and engineering. [4][5][6][7][8][9][10] The development has two basic directions, new and advanced methods for evaluation and description of the crystallization kinetics and the use of new experimental techniques.…”

“…[15][16][17][18] Nowadays, this technique is extensively used to study the crystallization and nucleation kinetics of polymers. 7,9,10,[18][19][20][21] For characterization, prediction and simulation of the crystallization kinetics, principally two different approaches are used: the isoconversional kinetics and the use of models of the crystallization kinetics. In the case of isoconversional kinetics, the effective activation energy as a function of the crystallinity is determined from measured curves.…”

“…Mechanical properties like shrinkage, impact behavior or stiffness, and optical properties are strongly influenced by the crystallinity . The investigation and simulation of polymer crystallization during cooling is an ongoing task in polymer science and engineering . The development has two basic directions, new and advanced methods for evaluation and description of the crystallization kinetics and the use of new experimental techniques.…”

“…One of these techniques is the fast scanning calorimetry (FSC) based on chip sensors . Nowadays, this technique is extensively used to study the crystallization and nucleation kinetics of polymers …”

Influence of TiO2 nanoparticles on nonisothermal crystallization of PP in a wide range of cooling rates analyzed by fast scanning DSC

“…The development of such high performance DSCs has helped to achieve breakthrough knowledge in the field of polymer crystallization in a much wider temperature/supercooling range than on application of DSC. This technique has given new insights into crystallization, melting behavior, glass transition, and structural reorganization under fast cooling of various polymers such as PA 6, PA 11, PBT, PET, PLA, PTFE, PB, and iPP …”