Study On Mechanics And Thermostability Of PBS/PPC Composition Reinforced By Whiskers

Biodegradable polyester resin is a kind of environmental material with high expectations of replacing the general plastics, which has excellent biodegradation and biocompatibility. At present, some biodegradable polyesters, including polylactic acid (PLA), poly(butylene succinate) (PBS), poly(propylenecarbonate) (PPC), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), have realized industrialization and been used widely in the fields of packaging, tableware, agricultural film and biomedical polymer. These polymers can be synthesized from the petrol raw materials or the fermentation products of biopolymers, especially some of which can also be synthesized via biotransformation of microorganism. PBS possesses similar mechanical strengths and processability to low density polyethylene, which can be modified by copolymerization or blend to improve the properties, cut the cost and expand the application fields. One important strategy is to bend inorganic filler with PBS, thus to raise the research interest and difficulties concerned with the interface between PBS and inorganic fillers. PPC has excellent application prospect in packaging and some particular fields due to its well biodegradation, oxygen barrier and high storage modulus.Herein, calcium carbonate whisker (CCW), calcium sulfate whisker (CSW) and magnesium salt whisker (MSW) as inorganic fillers have been used to prepare PBS/PPC compositions reinforced by inorganic whiskers via blending. The effect of the whiskers, the surface modification by coupling agent and epoxy on the mechanics, thermal stability and interfacial properties of the PBS/PPC compositions were explored through FT-IR, XPS, TGA, and DSC. The experiments indicate that CCW and CSW can enhance the mechanical properties of PBS and PPC matrix, and can improve crystallization performance and the thermal stability of the composites to a certain extent. After surface modification by coupling agent, the mechanical properties of the composites have been improved and the flexural strengths of the composites increase significantly. CCW, CSW, and MSW can greatly improved the mechanical properties of PPC, among which CSW shows the best performance in improving mechanical properties of PPC, but easily leads to the degradation ofPPC in the processability processes. MSW can improve considerably the mechanical properties of the PBS/PPC composites. Coupling agent and epoxy can improve the surface hydrophobicity of MSW. Modified MSW by coupling agent covered by epoxy have the best surface hydrophobicity. The mechanical tests indicate that, when the MSW addition is 30 wt%and composite modification by coupling agent and epoxy, the mechanical property is maximum with bending strength being 61.78MPa and the tensile strength being 35.63 MPa. The tests of thermal degradation kinetics indicate that modified MSW by epoxy can increase the thermal degradation activation energy of PBS/PPC composites, thus to enhance the thermal stabilities of the composites. The tests of crystallization kinetics show, when the addition of MSW being 5 wt%and the crystal cooling rate being 2 ℃·min1,the crystallinities of the M-MSWPBS/PPC composites modified by the coupling agents, epoxy and coupling agents-epoxy are 33.22,33.66,33.44%respectively, increasing 0.72,1.16 and 0.94%compared to the unmodified M-MSWPBS/PPC composites.Our work presents the research on the blending modification and applications of PBS and PPC composites, which provides the basic data for the further design and utilization of completely biodegradable materials. The replacement of biodegradable PBS/PPC composites for polyolefine can prevent traditional polymers from polluting the environment, which shows positive social and economic significances.