Study On The Relationship Between Structure And Properties Of Liquid Phase Bulk-gas Phase Impact Copolymerized Polypropylene

Impact copolymer polypropylene(IPC)as an excellent resin material by polymerizing a polypropylene alloy(PPc)prepared in the reactor.Due to the special process,the structure and shape of PPc and its complexity make it significantly improve its impact resistance and have good rigidity,which is comparable to engineering plastics.It has been widely used in the fields of automobiles and home appliances.IPC is a multi-component multi-phase formed by polymerization in a kettle and has a complex chain structure and a phase-form polymer.In this work,IR,TREF,GPC,DSC,DMA,SEM,rotational rheometer and other characterization methods were used to systematically study the chain structure,composition and intercomponent phase of automotive IPC with a melt index of 27g/10 min.Capacitive,phase morphology,dynamic rheology and product performance of different process parameters,found several factors to improve product performance,guided the processing and production,improved product performance,the paper achieved the following conclusion:(1)Using single solvent n-octane,IPC is divided into three components using TGEF,namely F50,F100 and F125.The analysis results show that F50 is mainly ethylene-propylene random copolymer(EPR),which contains very little crystallizable short-sequence structure of PE;F125 is mainly a propylene homopolymer(HPP),which is the matrix of the entire IPC.The long sequence of PP is mainly present in the components and is the key to determining the rigidity of the material.;F100 is mainly ethylene-propylene block copolymer(EbP),which has a broad molecular weight distribution and has many crystals of different segment lengths,which may be a bridge connecting EPR and propylene homopolymer.In addition,it was found that IPC has two phase transitions,and the three components obtained by fractionation show only one phase transition,and the phase transition of ethylene-propylene random copolymer and ethylene-propylene block copolymer is different.Not large,but also slightly different from the IPC temperature change,indicating that there may be interactions and interactions between the various levels;Compared with different IPC ethylene-propylene block copolymers,it is found that the difference in partial crystal structure is different,which may be caused by different catalyst systems or different production processes of different manufacturers;Successive self-nucleation annealing(SSA)found that when EbP component and EPR component were blended,EbP was diluted by EPR,and when HPP component and EbP component were blended,eutectic was formed between HPP and EbP.It is proved that there is an interaction between the three components,which also indicates that there is good compatibility between the components.(2)By observing the morphology of IPC,EPR/HPP binary solution blend and EPR/EbP/HPP ternary solution blend,IPC has uniform pore size and pore distribution.Combined with the thermal behavior of the blend,it is proved that the interfacial tension of each phase is small,and the two phases have macroscopic phase homogeneity and good compatibility.Observation of the SEM image of the solution blend revealed that when the EbP component is added,the drawn material appeared on the fracture surface,which is considered to enhance the compatibility of the EPR phase and the HPP phase when EbP was added.The fracture morphology different from the EPR/HPP binary blend appeared,which proved that the addition of EbP component enhanced the toughness of IPC and played the role of a compatibilizer.(3)The dynamic rheological behavior of IPC,fractions(EPR,EbP,HPP)and different ratios of solution blends(EPR/EbP,EbP/HPP)at various stages indicates.In the low frequency region,it deviates from the linear viscoelastic theory behavior,and the degree of deviation is slightly different.In addition,the study found that the main role of IPC is the dispersed phase EPR and matrix HPP,but EbP plays a compatibilizing role in the process of self-assembly,making the mechanical properties of the material better.(4)Through the study of process parameters,it is found that the distribution ratio of the loop reactor and the hydrogen content in the propylene homopolymer after high-pressure flashing are the key to control the size and distribution of the dispersed phase,and the control process is not changed without changing the catalyst system.Parameters are the key to producing high performance IPC.