The preparation and crystallization of long chain branching polylactide made by melt radicals reaction |
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| Authors: | Jinxiu You Lijuan Lou Wei Yu Chixing Zhou |
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| Affiliation: | 1. Advanced Rheology Institute, Department of Polymer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China;2. Petrochemical Research Institute, Petrochina, Beijing 100195, People's Republic of China |
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| Abstract: | Long chain branching (LCB) of polylactic acid (PLA) was successfully prepared by melt radicals reaction with pentaerythritol triacrylate (PETA) and bis (1‐methyl‐1‐phenylethyl) peroxide (DCP). The topological structure of the LCB was investigated by rheology and branch‐on‐branch (BOB) model was used to estimate the exact chain structures of the products, where comb‐like LCB structures were generated due to the complex coupling between different macro‐radicals. LCB structure was found to affect the crystallization of PLA products. In the temperature range of 110–130°C, the crystallization rate parameter (k) was improved sharply and the half crystallization time was decreased significantly after the grafting of PETA, which was ascribed to the enhanced hydrogen bonding in PETA‐grafted long chain branching PLA. By comparing with the LCB PLA made from chain extension using multifunctional monomer, it shows that the crystallization becomes slower in a highly branched material with extremely long relaxation time if the effect of hydrogen bonding is similar. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 |
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| Keywords: | addition polymerization crystallization structure– property relations biopolymers and renewable polymers rheology |
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