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Modification Research on Reactive Blending of Poly (Β-Hydroxybutyrate-Co-Β-Hydroxybutyvalerate)

Author: MaZuoMing
Tutor: ZhangYong
School: Shanghai Jiaotong University
Course: Materials Science
Keywords: PHBV PDLLA PBS Melt blending Dynamic crosslinking Crystallization kinetics
CLC: TQ316.33
Type: Master's thesis
Year: 2008
Downloads: 16
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Abstract


This thesis uses the method for processing of the molten blend, to prepare a blend of poly (beta-hydroxybutyrate ester-CO-of β-hydroxy-valerate) / poly-lactic acid (PHBV / PDLLA), poly (β-hydroxybutyrate acid ester-co-β-hydroxyvalerate) / poly lactic acid (PHBV / PDLLA) dynamically crosslinked blends, poly (beta-hydroxybutyrate ester-CO-β-hydroxy-valerate) / poly butoxy acid butylene glycol ester dynamically cross-linked blend of (PHBV / PBS / DCP), and poly (β-hydroxyethoxy of butyrates-co-beta-hydroxy-valerate) / silica (PHBV / SiO 2 ) nanocomposites. Study the mechanical properties of the blend phase morphology, rheological behavior, crystallization behavior and thermal properties of nanocomposites morphology, crystallization kinetics and thermal decomposition properties. PDLLA is a completely biodegradable plastic does not rely on oil. PDLLA possible to improve the mechanical properties of PHBV to improve its tensile strength, flexural strength / modulus, elongation at break and impact strength. With the increase of the PDLLA content, PHBV / PDLLA blends gradually from the sea - island structure into bicontinuous phase structure. PDLLA able to significantly inhibit the thermal degradation of the PHBV high temperatures, to improve its thermal stability, and to broaden the processing window. PDLLA PHBV crystallization having heterogeneous nucleation effect, but so spherulite growth rate is reduced, the degree of crystallinity reduces. Dicumyl peroxide (DCP) of the PHBV / PDLLA dynamic cross-linking, different amount of crosslinking agent on the performance of crosslinked blends. The HAAKE mixer CPC blend torque and after cross-linking the gel content of the blend are with the amount of crosslinking agent increases. Mechanical test results show that the the same crosslinker (0.5 phr) different PHBV / PDLLA proportions significantly improve the dynamic cross-linking of PHBV / of PDLLA dynamic crosslinking after mechanical performance. Blend rheological experiments show that the the PHBV / of PDLLA after cross-linking, storage modulus, and complex viscosity are improved, and the gel phenomenon appears in the low frequency region. The scanning electron microscope (SEM) photographs show the dynamic crosslinking significantly reduces the the PDLLA in PHBV / PDLLA blend phase domains, the phase interface becomes ambiguous, conducive to improve the phase interface for interaction between. By differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (XRD) test results show that the cross-linking reaction PHBV crystallization significantly inhibited polarizing microscope (POM) PHBV spherulite morphology indicates that the observed The spherulite morphology becomes complete PHBV / PDLLA blends dynamic cross-linking. PBS is a semi-crystalline fully biodegradable plastic. PHBV with PBS after blending can improve the mechanical properties of PHBV, but the improvement is limited. Dicumyl peroxide (DCP) PHBV / PBS (80/20) crosslinked, the mechanical properties of the blend be significantly improved. Different DCP content of the dynamic crosslinking blends various performance impact. Stress - strain curve of 0.5 phr of DCP, PHBV / PBS blends dynamic cross-linking rate of elongation at break after pre-crosslinked 4-5% to over 400%, 80-100 times, while The sacrificial material yield strength, greatly improve PHBV brittle broaden its range of applications. Impact sectional SEM photograph of the analysis on the atomic force microscopic analysis (AFM), the The crosslinking reaction greatly improve the interaction between the two phases of the PHBV and PBS, the phase domains fuzzy improve process compatibility between. DSC, XRD analysis of PHBV / PBS blends after crosslinking to promote crystallization of the polymer, the initial crystallization temperature; through the POM observation to PHBV / PBS crosslinked 120oC under isothermal crystallization, PHBV spherulite density than the dynamic significantly increased before crosslinking. 2 system of PHBV / SiO by field emission scanning electron microscope (FE-SEM) the studied of PHBV / SiO 2 PHBV matrix dispersion, the results show that The PHBV / SiO 2 PHBV matrix good dispersion. The crystallization kinetics of the the SiO 2 has the role of a nucleating agent, thereby contributing to the formation of PHBV spherulites growth rate of spherulites. Thermal gravimetric analysis (TGA) results show that the temperature increased with the SiO 2 content increases nanocomposites of PHBV / SiO , PHBV TG.

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