Crystalline Structure And Morphology Of Poly(3-Hydroxybutyrate)under Restricted Conditions

In this paper,the two types limited crystallization of poly(3-hydroxybutyrate)(PHB)in PHB / PES / PVPH blends and in micrometer-scale building was studied by Polarizing Microscope(POM),Atomic Force Microscopy(AFM)and Wide Angle X-ray Diffraction(WAXD)and the crystalline morphology,crystal structure and surface morphology of the restricted crystals under limited conditions were studied in detail.The immobilized PHB / PES blends and the compatible PHB / PES / PVPH blends were investigated by POM.It was found that incompatible PHB / PES blends appeared phase separation phenomenon during spherulite growth,there are many small phase separation regions in the spherulites of PHB.These phase separation regions are PES components,PES cannot form spherulites in these small separation regions,and PHB / PES / PVPH blends system in the crystallization of phase separation did not occur.The effect of the change of the crystalline component content of PHB / PES /PVPH blends on the crystal morphology of the blends was studied by POM.It was found that the changed of spherulites morphology of PHB and PES with the increase of PES content,When the content of PES increased gradually from 20% to 80%,the amorphous region in PHB spherulites increased gradually,and the spheroidal growth of PHB became more complete,and PES spherulites became more complete,When the content of the content gradually increased,the concentration of the PES component in the blending system gradually increased,and the concentration of PHB gradually decreased.And three different crystalline morphology in the crystallization process were observed by POM: 1.The PES spherulites with low glass transition temperature could be grown in the PHB spherulites with high glass transitiontemperature that had been crystallized;2.PHB and PES spherulites grow in the same nucleus,and the crystallization rate of PHB is greater than the crystallization rate of PES.3.The PHB spherulites and PES spherulites grows through each other and penetrates through the spherulites and the crystallization rate of PHB is higher than the PES spherulites.The surface morphology of the penetrates spherulites of PHB and PES was studied by AFM.It was found that the lamellas of PHB in the blends was larger than that of pure PHB,and the lamellar stacks were arranged regularly.The amorphous regions between the plates were also larger the PES lamellaes in the blends are much smaller than those of the pure PES,and the lamellar aggregates are formed in the blends.The amorphous regions between the filaments are larger and in no regular way.The PES lamellas can grow in an amorphous region between the PHB lamellaes,thereby forming a penetrate spherulite.The crystal morphology of PHB under the confined conditions of microstructure was studied by POM.It was found that the formation of spherulites was observed when the film was thick.When the film was thin,there was no spherulite,and AFM was used to study the effect of different thickness The surface morphology of the study found that the thickness of the surface changes will change.When the same thickness film is imprinted with different templates,XRD is used to characterize and the position of the diffraction peak after the imprinting is changed.However,the diffraction peak position of the different size template XRD is the same,indicating that the imprinted PHB crystallization structure has changed,but the template size has no effect on the structure.Using the AFM with a hot table to study the PHB melting point after micron construction,it was found that the melting point of the PHB after the microstructure was reduced and the micro-lines were melted at 160 ° C.