Study On Preparation And Performance Of Biodegradable Polyurethane Elastomer

Growing global awareness of plastic pollution has created a demand for biodegradable materials.Compared with polylactic acid and poly adipic acid/butyl terephthalate(PBAT),the biodegradable polypropylene carbonate polyurethane elastomer(PPC-TPU)has the advantages of low cost and high mechanical strength.In this paper,three biodegradable materials,PPC-TPU/CS,PPC-TPU/TPS and PPC-TPU/PBAT,were prepared by blending PPC-TPU with corn starch(CS),Thermoplastic starch(TPS)and PBAT by melt blending method.The rheological behavior of three biodegradable materials was studied by capillary rheometer.The influencing factors of rheological behavior of biodegradable materials were studied.The influence of processing technology and raw material preparation on the mechanical properties and processing flow of the three biodegradable materials were studied.The results are as follows:(1)With the increase of corn starch content,the tensile properties of PPC-TPU/CS blends first increased and then decreased,and the elongation at break showed a decreasing trend.With the increase of TPS content,the tensile properties of PPC-TPU/TPS blends first increased and then decreased,and the elongation at break increased.(2)The shear thinning phenomenon of PPC-TPU/CS,PPC-TPU/TPS and PPCTPU/PBAT blends under shear force was observed by high pressure capillary rheometer,which indicated that PPC-TPU/CS,PPC-TPU/TPS and PPC-TPU/PBAT are nonNewtonian fluids,and PPC-TPU/TPS has better melt fluidity under strong shear action.(3)The non-Newtonian exponent n of PPC-TPU/PBAT blends decreases first and then increases,but the comprehensive processing property of PPC-TPU blends is still better than PPC-TPU blends.(4)The activation energy ?E of viscous flow is calculated by using the Arrhenius equation.The microcurrent activation energy of PPC-TPU/CS,PPC-TPU/TPS and PPCTPU/PBAT blends all showed a decreasing trend.The temperature sensitivity was PPCTPU/PBAT,PPC-TPU/TPS and PPC-TPU/CS.(5)With the increase of the content of PBAT,the tensile properties of PPCTPU/PBAT blends decreased first and then increased,and the elongation at break decreased.When the content of PBAT was 40%,the tensile strength and elongation at break of PPC-TPU/PBAT blends were 25.1MPa and 1320%,respectively.(6)Differential scanning calorimetry analysis showed that the glass transition temperature of the blends increased with the increase of PBTA content.(7)The repeated processing experiment of PPC-TPU/PBAT blends showed that the mechanical properties of the blends decreased significantly after the second and third processing,and the decrease rate was up to 50%.