Preparation And Properties Of Highly Elastic Transparent Polypropylene

In this paper,blending method was used to enhance the toughness of polypropylene(PP).By adding nucleating agent to change the transparency of PP,the mechanical properties,optical properties and microscopic morphology of the obtained PP blends were investigated,respectively.The isothermal crystallization kinetics of the PP blends with nucleating agent was analyzed,and the crystallization process was controlled to obtain a PP blends as medical material with high toughness and transparency.The performance of the polyolefin elastomer(POE)added to other polymers is improved,which could be used to replace PVC for endotracheal intubation.In the first part,the strength of the elastomer POE is improved by adding two types of PP(T30,RP334R-K)and linear low density polyethylene(LLDPE).After the addition of the polymer,the tensile strength of the POE was improved,but the impact strength and elongation at break decrease more,and the light transmittance and haze did not changed much.PP was toughened and modified by applying four elastomers(SEBS and three types of POE:DF 740,DF 840,DF 940).For the obtained PP blend,the elongation at break and the impact strength were greatly improved,among which PP-DF 940 was improved to the largest extent,and the toughening effect on PP was the best.With regard to the PP-POE-SEBS ternary blending,the toughness of the blend obtained was improved,but the transparency and haze decreased a lot.In the second part,the sorbitol nucleating agent DMDBS and the inorganic nanoparticle nucleating agent SiO2 nanoparticles were added to PP,and the mechanical properties of the PP blend after adding two nucleating agents were compared.Compared with PP-SiO2,the tensile strength of PP-DMDBS decreased less,which the elongation at break and the impact strength decreased,and the haze decreased most.The transparency of PP was the best when 0.2%of DMDBS was added.Scanning electron microscopy analysis showed that the dispersion of SiO2 nanoparticles was poor,and agglomerates could be seen.Polarizing microscope(PLM),Wide-angle X-ray diffraction(WXRD)and Differential scanning calorimeter(DSC)can all conclude nucleating agents to accelerate the crystallization rate,shorten the crystallization time and reduce the spherulite size.Isothermal crystallization kinetics also show that the nucleation effect of DMDBS is significantly better than SiO2.The properties of PP blends with nucleating agents and POEs can basically meet the standards for PVC as medical materials.In the third part,the strength of the elastomer POE is improved by adding two types of PP(T30,RP334R-K)and linear low density polyethylene(LLDPE).After the addition of the polymer,the tensile strength of the POE was improved,but the impact strength was lowered,meanwhile,the light transmittance and haze did not changed much.