文献类型：期刊文献

中文题名：In-situ Polymerization-modification Process and Foaming of Poly（ethylene terephthalate）

英文题名：In-situ Polymerization-modification Process and Foaming of Poly(ethylene terephthalate)

作者：Zhong Hua[1];Xi Zhenhao[1];Liu Tao[1];Zhao Ling[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China

年份：2013

卷号：21

期号：12

起止页码：1410

中文期刊名：Chinese Journal of Chemical Engineering

外文期刊名：CHINESE JOURNAL OF CHEMICAL ENGINEERING

收录：CSTPCD;;EI(收录号：20140317196821);Scopus;WOS:【SCI-EXPANDED(收录号:WOS:000329835900012)】；CSCD:【CSCD2013_2014】；

基金：Supported by the National Natural Science Foundation of China（21176070）; the National High Technology Research and Development Program of China（2012AA040211）; the Joint Research Project of Yangtze River Delta（12195810900）; the Specialized Research Fund for the Doctoral Program of Higher Education（20120074120019）; the Fundamental Research Funds for the Central Universities

语种：英文

中文关键词：poly（ethylene terephthalate）; in-situ polymerization-modification; supercritical carbon dioxide; molten-state foaming

外文关键词：poly(ethylene terephthalate); in-situ polymerization-modification; supercritical carbon dioxide; molten-state foaming

摘要：Most of traditional linear poly(ethylene terephthalate)(PET)resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures,which are not enough to support and keep cells.An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride(PMDA)or pentaerythritol(PENTA)as modifying monomers to obtain PETs with high melt strength.The influence of amounts of modifying monomers on the properties of modified PET was investigated.It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength.With increasing the amount of the modifying monomer,the melt strength of the modified PET increased.But when the amount of PENTA reached 0.35%or PMDA reached 0.9%,crosslinking phenomenon was observed in the modified PET.Supercritical carbon dioxide(ScCO2)was employed as physical foaming agent to evaluate the foaming ability of modified PETs.The modified PETs had good foaming properties at 14 MPa of CO2pressure with foaming temperature ranging from 265°C to 280°C.SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures,with cell diameter ranging from 35μm to 49μm for PENTA modified PETs and38μm to 57μm for PMDA modified ones.Correspondingly,the cell density had a range of 3.5×107cells·cm 3to 7×106cells·cm 3for the former and 2.8×107cells·cm 3to 5.8×106cells·cm 3for the latter.
Most of traditional linear poly(ethylene terephthalate) (PET) resins of relatively low molecular mass and narrow molecular mass distribution have low melt strength at foaming temperatures, which are not enough to support and keep cells. An in-situ polymerization-modification process with esterification and polycondensation stages was performed in a 2 L batch stirred reactor using pyromellitic dianhydride (PMDA) or pentaerythritol (PENTA) as modifying monomers to obtain PETs with high melt strength. The influence of amounts of modifying monomers on the properties of modified PET was investigated. It was found that the selected modifying monomers could effectively introduce branched structures into the modified PETs and improve their melt strength. With increasing the amount of the modifying monomer, the melt strength of the modified PET increased. But when the amount of PENTA reached 0.35% or PMDA reached 0.9%, crosslinking phenomenon was observed in the modified PET. Supercritical carbon dioxide (ScCO2) was employed as physical foaming agent to evaluate the foaming ability of modified PETs. The modified PETs had good foaming properties at 14 MPa of CO2 pressure with foaming temperature ranging from 265 degrees C to 280 degrees C. SEM micrographs demonstrated that both modified PET foams had homogeneous cellular structures, with cell diameter ranging from 35 mu m to 49 mu m for PENTA modified PETs and 38 mu m to 57 mu m for PMDA modified ones. Correspondingly, the cell density had a range of 3.5x10(7) cells.cm(-3) to 7x10(6) cells.cm(-3) for the former and 2.8x10(7) cells.cm(-3) to 5.8x10(6) cells.cm(-3) for the latter.