Preparation Of Polar Polyethylene By Organic Solvent Assisted Solid-phase Grafting Method

In this paper,two organic solvents A,B were used as swelling agent of polyethylene(PE)matrix and carrying agent of monomer and initiator,to assist in prepareing polar PE by solid-state graft.The influences of amount of swelling agent,swelling time and swelling temperature on the graft polymerization were investigated in detail.The organic swelling agent A to assist PE solid phase grafting modification is by a small amount of solvent(1-2 times the matrix quality)as swelling agent,dibenzoyl peroxide(BPO)or azobisisobutyronitrile(AIBN)as initiator,the monomer:acrylic acid(AA),styrene(St)and dual monomers(AA/St)grafted onto the PE backbone,and the effects of swelling and reaction process were studied in terms of grafting percentage(GP),grafting efficiency(GE)and gel content(GC)of grafted products.From the analysis of experimental,results that,low density polyethylene(LDPE)compare with the linear low density polyethylene(LLDPE)and metallocene polyethylene(MPE)are more prone to graft copolymerization.The optimum conditions of grafting process were obtained:amount of swelling agent A is 165w%of PE matrix,w(LDPE):w(AA):w(St):w(BPO)= 100:4:2:0.4,40 ? swelling 2 h,95 ? for 2 h,the product of GP,GE and GC reached 5.0%,83.3%and 9.8%respectively.In addition,the cross-linking inhibitor phosphite triphenyl phosphite(TPP)could inhibited crosslinking side reaction,the product of GC declined sharply without a significant reduction in GP at the same time,in these conditions to join 0.06 mL of TPP,but the product of GC to 3.7%,while GP can be maintained at 3.9%.At the same time,using organic swelling agent B assisted solid phase graft modification of PE,and GP as a index of the swelling effect of swelling agent,through analyzing the difference of the two swelling agents to determine the main factors of impact swelling effect.Appropriate reaction conditions:amount of swelling agent B is 140w%of PE,monomers dosage is 6%,molar ratio of two monomers(GMA:St)is three to one,the interfacial agent dosage is 1 mL,and reacted at 100 ? for 2 h after 6 h impregnation at 30 ?.Grafted products were characterized by Fourier transform infrared spectroscopy(FTIR)and thermal gravimetric analysis(TG).The FTIR results confirmed that both AA and St were grafted onto PE and the TG results indicate that LDPE grafted polar monomer with the improved thermal stability compared to the raw material LDPE.