Study On Blends Of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/Hyperbranched Polyesteramidesand (HBPEA) And Its Fiber Spinnability

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) are microbial polymers presenting the advantages of biodegradability,biosorption and biocompatibility.However,the application of PHBV has often been limited by some disadvantages,such as slow crystallization rate,poor thermal stability,easy hydrolysis,sticky and relatively difficult processing.Blending of PHBV has received considerable attentions in resent years.In this paper,Hyperbranched Polyesteramidesand(HBPEA) were selected as an additive to blend with PHBV.The thermal properties,crystallization behaviors,rheological behaviors have been investigated,and the spinnability of blend systems were analyzed by melting spinning too.In order to spinning the filaments that have a certain tensile strength and satisfied for the weaving in the laboratory,the optimum parameters of spinning for PHBV were brought up based above researches.First,the fundamental properties of the two materials have been characterized.The results indicated that the control of moisture content and processing temperature is a must to prevent its hydrolysis and its thermal degradation.The degradation temperature of HBPEA is higher than the processing one.The HBPEA has a stable performances and good dissolution in polar solvents.The mechanism of blending contains three parts,including the HBPEA ball shape's sliding properties, large number of stearic acid's lubrication and the benzene ring's rigidity existing in the blending system. Then we focus on the performances of the blending system.Through the comparison between the two additives of SiO₂ and HBPEA,some conclusions are apparently to conclude. Adding HBPEA to PHBV system,the disadvantages of high HV content PHBV system exist no more to increase the processing performances.Besides,the overall crystallization rates of PHBV are increased.Analysis of kinetic of the crystallization and its crystal structure showed that the content of the additives did obviously influence the mechanism of nucleation and grain size calculated from the X-ray diffraction.In addition,the mechanical properties of blending samples suggested that the improvement of the strength and the conversion from brittleness to toughness during the tensile process owe to the uniform dispersion of HBPEA in the PHBV melt.More importantly,the rheological properties of two blend systems were investigated as follows.The apparent viscosity of blending comprised of HBPEA has contributed to the processing possibility of PHBV/HBPEA blending system.So the additive ratios and the window of temperature for processing of PHBV was the most important elements to the PHBV/HBPEA blending system.Finally,the blending system has been studied about its spinning properties.The results show that the viscosity of PHBV system reduced with the hyperbranched polyester added.It made the fiber spinning became feasible.In the laboratory we can produce the PHBV fiber which has good mechanical properties and be able to meet the textile finishing through a series of spinning the adjustment and optimization of process conditions.These will develop the application of PHBV.