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4699254 
Journal Article 
Crystallization of poly(epsilon-caprolactone) blocks confined in crystallized lamellar morphology of poly(epsilon-caprolactone)-block-polyethylene copolymers: effects of polyethylene crystallinity and confinement size 
Sakurai, T; Nagakura, H; Gondo, S; Nojima, S 
2013 
1 
Polymer Journal
ISSN: 0032-3896 
45 
4 
436-443 
WOS:000317106400010 
In poly(epsilon-caprolactone)-block-polyethylene (PCL-b-PE) diblock copolymers, the crystallizable temperature of PE blocks is sufficiently higher than that of PCL blocks, and accordingly, PE blocks crystallize first on quenching to form a crystallized lamellar morphology (PE lamellar morphology), followed by the crystallization of PCL blocks. We have investigated the crystallization behavior and crystal orientation of PCL blocks spatially confined in the PE lamellar morphology with different crystallinities of PE blocks chi(PE) and layer thicknesses of PCL blocks d(PCL) as a function of crystallization temperature T-c,T-PCL, where chi PE and dPCL are related to the rigidity and confinement size of the PE lamellar morphology, respectively. We found from differential scanning calorimetry results that the crystallization behavior of PCL blocks in PCL-b-PE with higher vPE and smaller dPCL was significantly different from that in other PCL-b-PE copolymers. We also found using two-dimensional wide-angle X-ray diffraction that the orientation of PCL crystals changed moderately by changing Tc, PCL in PCL-b-PE with higher vPE and smaller dPCL, whereas it did not change substantially in PCL-b-PE with lower vPE or larger dPCL. These results indicate that the rigidity and confinement size of the crystallized lamellar morphology, both of which can be controlled through the crystallization of the first blocks, are key factors for the crystallization of the second blocks in crystalline-crystalline diblocks with different crystallizable temperatures. Polymer Journal (2013) 45, 436-443; doi:10.1038/pj.2012.164;published online 12 September 2012 
crystalline-crystalline diblock copolymer; crystallization behavior; crystal orientation; lamellar morphology