Preparation And Characterization Of Biodegradable PBS/Sisal Fiber Composites

Poly(butylene succinate)(PBS) is one kind of biodegradable polymer material with good performance, which has high melting point, good thermal stability,and good processing properties, and it has been applied in some industrial fields. But PBS also has some shortcomings, such as the bad rigid and the high price, it needs to be modified. In order to ensure its biodegradable properties, we choose natural sisal plant fiber as a reinforcing fiber, sisal fiber(SF) has processed great performance, whose source is rich and price is low, we can improve the performance and reduce the production cost at the same time.In this paper, SF/PBS composites were prepared by means of melt extrusion,and some sisal fiber surface pretreatment have been used to enhance the bond strength between the fiber phase and matrix phase, thus to improve the mechanical properties and biodegradation properties of composite materials, and expand its range of applications. The main contents are as follows:(1) The investigation of using coupling agent treated sisal fiber reinforced composites showed that the effect of silane coupling agent KH-550 was better than other silane coupling agents and titanate coupling agent, if coupling agent has not been used, we can not get composites because of the bad interface properties between sisal fiber and matrix PBS. While the content of KH-550 is 4wt%,we can get composites with good mechanical properties, too much or too little coupling agent will affect the mechanical properties of composite materials, compare to the neat PBS, the tensile strength of the composite is almost the same, but the flexural strength and impact strength respectively increase by 100% and 62%;while the content of sisal fiber is 25wt%,the mechanical properties of the composite are best.(2) The investigation of using the alkaline solution-treated sisal fiber reinforced composites showed that the optimal concentration of alkali treatment is 9g / L, a higher or lower concentration will both affect the mechanical properties of the composites, compare to the composite materials without alkaline solution treatment, the tensile strength increase by 10%, the flexural strength increase by 7%, the impact strength increase by 25%; with the injection pressure of 50 MPa, the holding pressure of 40 MPa, we can get composites with best mechanical properties.(3) The investigation of the microstructure of the composites showed that sisal fiber dispersed unevenly in the matrix when the sisal fiber content is less, while higher contents of sisal fiber can be woven into a mesh structure and undertake stress; without useing the coupling agent, fibers were mainiy pulled out from the matrix, while with useing the coupling agent, fibers were mainiy pulled off directly; moderate concentration of alkali treatment can enhance the interfacial bonding strength between the fiber and the matrix.(4) The investigation of the thermal properties of the composites showed that the addition of sisal fiber can improve the heat resistance of the composites, but the processing properties of the composites and thermal stability deteriorates, and the crystallinity also decreased; the surface pretreatment of sisal fiber can improve the heat resistance and thermal stability of the composite material, and improve the crystallinity of the composite material, but has little effect on the processability.(5) The investigation of biodegradation properties of composites showed that the addition of sisal fiber can accelerate the degradation of the composite material.With higher content of sisal fiber, the composite materials have faster degradation rate; the addition of sisal fiber also shortens the service life of materials; alkali-treatment also can accelerate the degradation of composites.