Morphological Structure And Properties Of Polypropylene(PP)/Polyethylene Terephthalate(PET) Blends

The reuse & recycling of garbage not only impact the environment,but are also related to the homeland on which human beings depend.The topic of PET recycling remains a difficult issue,which urgently needs solving and has attracted worldwide attention.This work is concentrated on PP/PET blend material without compatibilizer,PP/PET/PP-g-MAH blend material with different contents of compatibilizer.Mechanical properties,thermal stability,crystallization behavior,phase morphology,and thermal conductivity of the blends were analyzed in details.The mechanical test of the materials showed that with the increase of PET content,the tensile strength of the blends increased first and then decreased,while the tensile modulus gradually increased and the elongation at break decreased.After adding the compatibilizer,the tensile strength of the blend material became larger.The more the compatibilizer,the greater the tensile strength.When 10% compatibilizer was added and the PP/PET ratio was 80/20,not only the tensile strength of the blended material was the largest,but the tensile modulus was also the largest.The thermal stability analysis results of the samples showed that the residual carbon content of blends without compatibilizer increased with the increase of PET content.After adding the compatibilizer,as compared with the blends without the compatibilizer,it was found that the initial decomposition temperature was slightly reduced and the amount of residual carbon was reduced when the amount of the compatibilized agent was relatively small.When there was more compatibilizer,the initial decomposition temperature of the blends rose,and the amount of residual carbon was smaller.It was found from the non-isothermal crystallization behavior that when no compatibilizer was added,low content of PET had nucleation and crystallization effect on PP in the blends,while a high content of PET showed hindering effect on PP's crystallization.With the addition of compatibilizers,the crystal form in the blend remained unchanged,but PET had a certain promotion effect on the nucleation and crystallization of PP.SEM observation and rheological tests showed that whenPP/PET was simply blended,the compatibility was very poor,and obvious sea-island structures appeared.The more the PET content,the more obvious the particle size.In addition,the dynamic rheological test showed that the viscosity,storage modulus,and complex modulus of the blended materials decreased with increasing temperature.Dynamic temperature scanning suggested that when the PP/PET ratio was 80/20,the stability of the blends was perfect.Compatibilizers have significantly improved the compatibility of PP and PET,and a 10% dose not only increased the phase separation temperature,but also made the blends more stable.Moreover,the PP/PET/PP-g-MAH ratio was selected to be 80/20/10,and the PP/PET/Fe antistatic composites were further prepared.The effects of the amount of Fe powder on the crystallization properties,thermal stability,phase morphology,rheological behavior,and electrical and thermal conductivity of the composites were studied.From the perspective of thermal stability,the addition of Fe powder increased the residual carbon content of the composites.The addition of Fe powder hardly changed the crystalline form of PP in the composite,but it had a certain hindrance to the crystallization of PP during the cooling and crystallization of the material.The rheological behavior indicated that the addition of Fe powder increased the complex viscosity of the composite material to a certain extent,and also improved the storage modulus and composite modulus of the composites,indicating that the addition of Fe powder improved the stability of the composite material.In terms of thermal conductivity and electrical conductivity,the addition of Fe powder can improve the thermal conductivity of the composite material.Three classical thermal conduction models were also adopted and compared with the experimental thermal conductivities,among which the Agari model presented the most reasonable prediction.Considering the electrical conductivity was considerably improved,it was obvious that PP/PET/Fe composites displayed acceptable antistatic properties,which provides a facile way for the application of recycled PET.