TY - GEN
T1 - Isothermal crystallization behavior of isotactic polypropylene/polyhedral oligomeric silsesquioxane nanocomposites
AU - Chen, Jean Hong
AU - Chen, Hsin Lung
AU - Chuang, Wei Tsung
AU - Jeng, U. Ser
PY - 2010
Y1 - 2010
N2 - The isothermal crystallization kinetics and morphology developments of iPP/POSS nanocomposites presented an unusual crystallization behaviors. The exothermic morphologies of isothermal crystallization of iPP/POSS composites changed remarkable with increasing POSS. Moreover, the morphology development of spherulitic for iPP/POSS composites showed the POSS molecules became nanocrystals firstly and then aggregated together forming thread- or network-like morphologies at very small loading of POSS. It implies that the POSS nanocrystals appeared an effective nucleating agent for iPP to promote the nucleation rate and to retarde the growth rate of iPP during crystallization. Therefore, the isothermal crystallization showed a single exothermic peak at lower POSS content, whereas, at larger POSS content, which displayed the multi-exothermic peaks during isothermal crystallization corresponded to the POSS molecules were both influenced the terms of transport the molten iPP chain and formation the critical nuclei of iPP. The crystallization mechanisms of multiexothermic peaks may proceed to combine the "nucleating agent inducing nucleation rate of iPP"and "network structure of POSS nanocrystals retarding growth rate of iPP"due to the network structure of POSS nanocrystals retarded the molted iPP chains diffusing and folding rate during crystallization. Therefore, in this work, we proved the multi-exothermic morphologies of iPP/POSS composites by Hoffman and Lauritzen theory. The majority POSS nanocrystals essentially acted an effectively nucleating agent role to reduce the energy required for formation of the critical size iPP nuclei, Kg, attributed to decrease in the fold surface free energy, ?e, of iPP during nucleation. Whereas, some minority POSS molecules, dispersed at the molecular level in the bulk region, presented an effectively inhibiting agent to retard the growth rate of iPP corresponded to increase in the activation energy of polymer segments, U*, from melted region transporting to the crystal surface as POSS content is increased.
AB - The isothermal crystallization kinetics and morphology developments of iPP/POSS nanocomposites presented an unusual crystallization behaviors. The exothermic morphologies of isothermal crystallization of iPP/POSS composites changed remarkable with increasing POSS. Moreover, the morphology development of spherulitic for iPP/POSS composites showed the POSS molecules became nanocrystals firstly and then aggregated together forming thread- or network-like morphologies at very small loading of POSS. It implies that the POSS nanocrystals appeared an effective nucleating agent for iPP to promote the nucleation rate and to retarde the growth rate of iPP during crystallization. Therefore, the isothermal crystallization showed a single exothermic peak at lower POSS content, whereas, at larger POSS content, which displayed the multi-exothermic peaks during isothermal crystallization corresponded to the POSS molecules were both influenced the terms of transport the molten iPP chain and formation the critical nuclei of iPP. The crystallization mechanisms of multiexothermic peaks may proceed to combine the "nucleating agent inducing nucleation rate of iPP"and "network structure of POSS nanocrystals retarding growth rate of iPP"due to the network structure of POSS nanocrystals retarded the molted iPP chains diffusing and folding rate during crystallization. Therefore, in this work, we proved the multi-exothermic morphologies of iPP/POSS composites by Hoffman and Lauritzen theory. The majority POSS nanocrystals essentially acted an effectively nucleating agent role to reduce the energy required for formation of the critical size iPP nuclei, Kg, attributed to decrease in the fold surface free energy, ?e, of iPP during nucleation. Whereas, some minority POSS molecules, dispersed at the molecular level in the bulk region, presented an effectively inhibiting agent to retard the growth rate of iPP corresponded to increase in the activation energy of polymer segments, U*, from melted region transporting to the crystal surface as POSS content is increased.
KW - Ipp/poss composites
KW - Isothermal crystallization kinetics
KW - Nucleating agent inducing crystallization
UR - http://www.scopus.com/inward/record.url?scp=84905466279&partnerID=8YFLogxK
M3 - 会议稿件
AN - SCOPUS:84905466279
SN - 9781632660756
T3 - 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010
SP - 1127
EP - 1130
BT - 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010
PB - ACCM-7 Organizing Committee
T2 - 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010
Y2 - 15 November 2010 through 18 November 2010
ER -