In this paper, melt crystallization of poly(ether ether ketone ketone)(PEEKK) under strong electric field was investigated. In the crystal structure of PEEKK, the length of c axis was found to be 1.075 nm, increasing ...In this paper, melt crystallization of poly(ether ether ketone ketone)(PEEKK) under strong electric field was investigated. In the crystal structure of PEEKK, the length of c axis was found to be 1.075 nm, increasing by 7% compared to that of PEEKK crystallized without strong electric field. The molecule chains might take a more extended conformation through the opening of the bridge bond angles by increasing from 124° to 144° under strong electric field in the crystal structure.展开更多
The melting and recrystallization behaviour of poly（vinylcyclohexane）-b-poly（ethylene）-b-poly（vinylcyclohexane）（PVCH-PE-PVCH） triblock copolymer in supercritical carbon dioxide(CO2) was investigated by（using...The melting and recrystallization behaviour of poly（vinylcyclohexane）-b-poly（ethylene）-b-poly（vinylcyclohexane）（PVCH-PE-PVCH） triblock copolymer in supercritical carbon dioxide(CO2) was investigated by（using） of DSC.The effect of the rate of the depressurization of CO2 on the crystallization of the samples was also examined.It is found that there are three melting peaks on each DSC curve of the samples treated in supericritical CO2 at the temperature above tm of the untreated PVCH-PE-PVCH.They corresponded to the 'hard' confined crystallization of PE blocks homogeneous nucleation,the 'soft' confined crystallization of PE blocks homogeneous nucleation and the self-seeding nucleation free crystallization of PE blocks respectively.Furthermore,these three kinds of crystallization could be controlled by changing the competition between the crystallization of PE block and the vitrifaction of PVCH block in the samples,which depended on the rate of the depressurization of CO2.展开更多
文摘In this paper, melt crystallization of poly(ether ether ketone ketone)(PEEKK) under strong electric field was investigated. In the crystal structure of PEEKK, the length of c axis was found to be 1.075 nm, increasing by 7% compared to that of PEEKK crystallized without strong electric field. The molecule chains might take a more extended conformation through the opening of the bridge bond angles by increasing from 124° to 144° under strong electric field in the crystal structure.
文摘The melting and recrystallization behaviour of poly（vinylcyclohexane）-b-poly（ethylene）-b-poly（vinylcyclohexane）（PVCH-PE-PVCH） triblock copolymer in supercritical carbon dioxide(CO2) was investigated by（using） of DSC.The effect of the rate of the depressurization of CO2 on the crystallization of the samples was also examined.It is found that there are three melting peaks on each DSC curve of the samples treated in supericritical CO2 at the temperature above tm of the untreated PVCH-PE-PVCH.They corresponded to the 'hard' confined crystallization of PE blocks homogeneous nucleation,the 'soft' confined crystallization of PE blocks homogeneous nucleation and the self-seeding nucleation free crystallization of PE blocks respectively.Furthermore,these three kinds of crystallization could be controlled by changing the competition between the crystallization of PE block and the vitrifaction of PVCH block in the samples,which depended on the rate of the depressurization of CO2.
