Study And Preparation Of Low Extraction And Heat-Resistant BOPET

Biaxially oriented Polyester film(BOPET)with excellent performance shows a wide range of applications from packaging to electron,optics,image,magnetic,etc.But BOPET film still has some defects,such as produce oligomer,low heat resistance level,especially as electrical insulating material.In order to prepare the low oligomer extraction and heat-resistant BOPET,this thesis mainly study and select suitable PET chip and additives as materials.With respect to the above considerations,the results are as follows:1.The thermal ageing experiments of PET fibers were done in the blast oven at 210?,220? and 230?,respectively.The intrinsic viscosity,content of carboxyl end group,xylene extraction and fracture strength of fiber samples were measured.The results showed that the decrease of intrinsic viscosity and the growth of carboxyl end group content(CV)of PET during the thermal aging is the first order reaction,the xylene extraction value with the extension of heat aging temperature and the thermal aging time increased.Fitting is made to the loss of strength and found that the strength loss of PET fiber is the third-order reaction.The results revealed the change laws of PET properties in thermal aging,and those methods can be used to study the thermal performance of PET.2.In the research work of this group,PMDA was tried as an extender of PET to obtain the high viscosity of PET samples.By compared the intrinsic viscosity and CV of PET samples with different PMDA content,the results showed that a little of PMDA can increase the viscosity and reduce the CV of PET during the melting process.But excessive PMDA could accelerate the degradation of PET,decrease the intrinsic viscosity and increase the CV of PET samples.The DSC tests were conducted on PET/PMDA samples,the results showed that the addition of PMDA can damage the regularity of molecular chain,so that the crystallization of PET becomes more difficult,the crystallinities decreased,and the melting point also decreased.The PET/PMDA by injection molding were made of dumbbell shaped samples,and the thermal ageing experiments for PET dumbbell shaped samples were done in the blast oven at 220?,then the tensile strength of samples were measured before and after ageing.The experimental results showed that,compared to the samples without PMDA,the samples with 1wt%PMDA have a higher initial tensile strength,and still kept the higher strength after thermal ageing,it indicated that increasing the molecular weight of PET can improve its heat aging properties.3.By melt blending,the DSC test,the determination of intrinsic viscosity and other characterization methods,this paper studied the influence of IPA,BaSO4 and antioxidant on thermal performance of PET.The results showed that the addition of IPA can damage the regularity of the molecular chain of PET,lower the crystallization ability of PET,but also reduce the melting point of PET.Therefore,the addition of IPA can reduce the processing temperature so that reduce the formation of oligomer during the melt processing.BaSO4 can improve the crystallization rate and crystallinity of PET as the nucleating agent,and the antioxidants can alleviate the thermal oxidative degradation of PET at high temperature.The masterbatch was prepared by twin-screw extruder used PBT chip,BaSO4 and antioxidant 300 as raw materials.The fibers were spun by melt spinning using PBT masterbatch mixed PET chip([?]=0.8,IPA 1.7wt%).Compared the xylene extraction and the loss of tensile strength of fibers,the results showed that the fiber with 2.5wt%masterbatch has good heat resistance,and the content of xylene extraction is low.4.Four kinds of BOPET film were prepared through drying,melting,casting thick film,biaxially oriented and heat shaping.The XRD,hot-shrinkage rate,xylene extraction and tensile strength after thermal aging were conducted,the results showed that the BOPET film with high intrinsic viscosity PET chip([?]=0.8,IPA 1.7wt%)and PBT masterbatch(2.5wt%)as raw materials has a higher crystallinity,good heat aging resistance,and the xylene extraction values less than 0.6%.But the dimensional stability of this film is not better than other films.