Characterization&Research Of Poly(Ethylene Terephthalate) Composite

The low intrinsic viscosity, poor thermal stability and etc. limited rPET recyclingapplications. This paper theoretically studied PET chain extending, nucleating,toughening and strengthening mechanism during its recycling applications.2,2-(1,4-phenylene)bis(2-oxazoline)(PBO),1,4-butanediol diglycidyl ether(BDE),1,6-hexanediol diglycidyl ether(HDE), glycol diglycidyl ether (GDE) andADR-4370s(ADR) purchased from BASF company were selected as PET chainextenders. The most effective chain extender was compared with different qualitycontent. By DSC, XRD, IR, TG, SEM and other testing methods we studied the intrinsicviscosity, mechanical properties, crystal properties of PET. It was indicated that HDEwas the most effective chain extender and can significantly improve the strength of thematerial. With addition of0.6wt%, the intrinsic viscosity was promoted from0.58dl/g to0.76dl/g, tensile strength from57.8MPa to66.4MPa, the flexural strength from78.0MPa to88.1MPa, thermal crystallization peak value increased from200.6℃204.5℃,the glass transition temperature decreased from79℃to76℃which indicated thepresence of HDE was beneficial for material crystallization. Utilizing HDE as chainextender, Talc as nucleating agents, POE-g-GMA as toughener, GF as enhancer and tomodify PET processing flow, thermal stability, mechanical, etc., PET compositematerial was prepared. The results showed that the composite tensile strength turned outto be63.6MPa, bending strength87.0MPa, impact strength9.35kJ/m2, melt index17.97g/10min which satisfied the processing requirements with better thermal stability—initiation, termination, and the maximum decomposition temperature of the materialwere increased.The performance of rPET was not as same as PET. On the one hand the presence ofimpurities such as hot-melt adhesives, PVC and other materials caused the materialthermal degradation during processing. On the other hand, they can be nucleating agentto accelerate the crystal rate and increase crystallinity in the procedure of cooling. HDEand ADR were chosen as rPET chain extenders. It was indicated that optimum additionof ADR was0.5wt%with the intrinsic viscosity increasing from0.19dl/g to0.50dl/g;optimum addition of HDE was1.0wt%with the intrinsic viscosity0.38dl/g. UnlikeADR, HDE had less effect on rPET chain extend, HDE can accelerate the degradationof the material. Although ADR was more obviously effective, when ADR was addedexcessively, the rPET solution existed gel, rPET cannot be completely dissolved. Utilizing ADR as chain extender, Talc as nucleating agents, POE-g-GMA as toughener,GF as enhancer and to modify PET processing flow, thermal stability, mechanical, etc.,rPET composite material was prepared. The results showed that the composite tensilestrength turned out to be88.4MPa, bending strength152.9MPa, impact strength12.3kJ/m2which suggested the toughness of the material promoted significantly, meltindex9.65g/10min.DSC was used to study non-isothermal crystal kinetics of composite materials. Itwas indicated that the crystal rate changed little during the initial crystallization andsecondary crystallization stage; Nucleating effect of Talc was not obvious, becauseimpurities can be used as heterogeneous nucleation during material’s crystallization.Talc’s presence obstructed the movement of molecules, as the evidence showed thecrystal rate constant—Zcdecreased, the Avrami constant—n was about2whichindicated the crystal growed mainly in two dimensions.