Fractionated crystallization, polymorphic crystalline structure, and spherulite morphology of poly(butylene adipate) in its miscible blend with poly(butylene succinate)

Crystalline and Spherulitic Morphology of Polymers Crystallized in Confined Systems

“…Similar phenomena have also been observed in the PBS/PEO [89] and PBAS/PEO blends [95]. As shown in Figure 9, PBA cannot form its own spherulites in crystallization, and the crystallization of PBA did not change the PBS/PBA blend is another miscible system showing the confined and fractional crystallization behavior, in which both components have similar chemical structures and are biodegradable [94]. Fractional crystallization of PBA component occurring in the PBS/PBA blends depended strongly on the content and T c of the PBS component; this was related to the distribution of PBA in the PBS phase.…”

“…Researchers have found that the binary miscible crystalline/crystalline polymers show the confined and fractional crystallization behavior because of the phase separation and segregation in different length scales during crystallization process. These crystalline/crystalline polymer blends included poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) [75], poly(3-hydroxybutyrate) (PHB)/poly(ethylene oxide) (PEO) [76,77], poly(vinylidene fluoride) (PVDF)/poly(butylene adipate) (PBA) [78][79][80], PVDF/poly(butylene succinate-co-butylene adipate) (PBSA) [81], PVDF/PHB [82], PVDF/poly(butylene succinate) (PBS) [83][84][85], PBS/PEO [86][87][88][89][90][91][92], PBS/PBA [93,94], poly(butylene adipate-co-butylene succinate) (PBAS)/PEO [95], poly(ethylene succinate) (PES)/PEO [96], PLLA/poly(oxymethylene) [97,98], and so on. Expect for the miscible blends with one or two crystalline homopolymers, the miscible copolymer/copolymer blends having crystalline components or blocks could also show the confined crystallization behavior [99,100].…”

“…These interlamellar, interfibrillar or interspherulitic environments will exert diversified confinement effects on the following crystallization of the low-T m component. The low-T m component will show the different crystallizabilities when segregated in different environments; this leads to the multistage and fractional crystallizations of the low-T m polymer component [78,79,81,84,87,88,90,91,[93][94][95]. Therefore, the crystalline/crystalline miscible…”

“…Crystallization of PBS did not change the extinction feature of the preexisting PVDF spherulites, implying that the PBS component crystallized in the lamellar crystals with the same orientation as PVDF. PBS/PBA blend is another miscible system showing the confined and fractional crystallization behavior, in which both components have similar chemical structures and are biodegradable [94]. Fractional crystallization of PBA component occurring in the PBS/PBA blends depended strongly on the content and Tc of the PBS component; this was related to the distribution of PBA in the PBS phase.…”

“…Crystallization of PBA was suppressed in the PBA/PBS blend, due to the physical confinement effects of PBS crystals. According to the morphological observation, Yang et al have found that the spherulite growth direction of PBA was influenced by that of PBS in the PBS/PBA blends [94]. Figure 9 shows the POM micrographs of PBS/PBA 50/50 blends in the two-step crystallization process.…”