Effect of Architecture on the Crystal Morphology of Block Copolymers. Small-Angle X-ray Scattering and Differential Scanning Calorimetry

Comparison of Crystallization Rate and Macroscopic Morphology of Two Oxyethylene/Oxybutylene Triblock Copolymers. The Effect of Molecular Architecture

“…4 Previous studies on the solid structures of oxyethylene/oxybutylene diblock and triblock copolymers preferred to the conclusion that the crystal lamellar thickness of the E block is parallel to the ''long period'' direction. 9,11,12 There are two possibilities for the structure of the E domains. Firstly, the E domains may consist of crystalline E layer and amorphous E layer, and the lamellar thickness of the E crystals, L c , is calculated by:…”

“…7,8 The structures of oxyethylene/oxybutylene diblock and triblock copolymers (represented by E m B n , B n/2 E m B n/2 and E m/2 B n E m/2 , where E is oxyethylene unit and B is oxybutylene unit) in the melt and in the solid state have been systematically compared in terms of the overall length of the block copolymer and the length of single E block. 2,4,9 It has been shown that B n/2 E m B n/2 and E m/2 B n E m/2 triblock copolymers have similar structure including long period and melting temperature, though their order-disorder transition temperatures are different. 2,4,9 However, in B n/2 E m -B n/2 triblock copolymer the central crystallizable E block is connected with amorphous B block at both ends of the E block, whereas in E m/2 B n E m/2 both ends of the amorphous B block are immobilized at the interface when crystallized from micro-phase separated state.…”

“…2,4,9 It has been shown that B n/2 E m B n/2 and E m/2 B n E m/2 triblock copolymers have similar structure including long period and melting temperature, though their order-disorder transition temperatures are different. 2,4,9 However, in B n/2 E m -B n/2 triblock copolymer the central crystallizable E block is connected with amorphous B block at both ends of the E block, whereas in E m/2 B n E m/2 both ends of the amorphous B block are immobilized at the interface when crystallized from micro-phase separated state. Since both the B block and the E block change their conformation during crystallization, crystallization of the E block is inevitably affected by the amorphous B block.…”

Crystallization of Poly(ethylene terephthalate) in Poly(ethylene terephthalate)/Bisphenol A Polycarbonate Block Copolymers: Influence of Block Length and Role of the Rubbery Amorphous Component

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] The role of the block length in influencing the crystallization behavior is considered fundamental: it was found that the extent of folding increases with length of both crystalline and amorphous blocks, influencing melting temperature and enthalpy. [13,[15][16][17][18][19] The transesterification reactions performed in the molten state generally give copolymers with a broad block length distribution due to the poor control on the macromolecular structure. A wide literature analyzes these materials mainly Summary: Analysis was made of the crystallization of the PET blocks in PET/PC copolymers as a function of the block length, varying from M n ¼ 5300 to 17100 g Á mol À1 (X n PET ¼ 28-89, PET monomeric sequences).…”

“…These analyses are mainly carried out on di‐ or triblock copolymers with a narrow block length distribution and a well defined structure 1–14. The role of the block length in influencing the crystallization behavior is considered fundamental: it was found that the extent of folding increases with length of both crystalline and amorphous blocks, influencing melting temperature and enthalpy 13,15–19…”