高能辐射与增容剂在混杂聚烯烃回收中的作用研究

研究快讯c合成橡胶工业,2002-01ommunicationsCHINA SYNTHETIC RUBBER INDUSTRYEffects of high energy radiation and compatibilizer on toughness andmorphology of recycled hybrid polyolefinsCollege of Materials Science and Engineering, Beijing Unirersity of Chemical Technology, Beijing 100029, China)Polypropylene(PP), high- density polyethylene( HDPE)and irradiation, the chain scission may be prevail, as a result, alow-density polyethylene(LDPE )are three most widely used maximum of impact strength was exhibitedFrom Fis c in aon e ten when ne conmaeibilit tea icarusually mixed and recycled together. However, the three are diation was employed, the fracturedmiscible resulting in phase separation and poor mechanical phase separation (a). When EPDM was introduced witheproperties 1 2. In this paper, a mixture of approximately equal radiation, the boundary of the phases became smeared(b)mass of used PP, HDPE and LDPE was taken as a model sys- After irradiation, not only the surface became more unifortem, which will be denoted as post-customer-resin(PCR)The waste plastics were received in the form of film and werecut into small pieces before use. Three measures were taken tothe properties of PCR: introducing fresh HDPEducing fresh HDPE and a compatibilizer; subjecting the blendsof PCR, fresh HDPE and a compatibilizer to y-radiation. Alhe fresh resins and the PCR were mechanically mixed and fed(a)to a single serew extruder, in which they were extruded at ascrew speed of 40 r/min and temperatures varied from 145Cat the feed zone increased to 190 C at the final zone and 183℃ at the die.From Table 1, one may conclude that the toughening effect ofEPDM was much higher than that of EvA. which was deter-mined by the chemical nature of the two. EPDM is essentiallyMass ratio: PCR/HDPE/EPDM=80/20/0(a, c)composed of units of ethylene and propylene, its compatibili80/15/5(b, d); Irradiation dose: 0 kGy(a, b): 70 kGy(e, d)ing and toughening effects were naturally better. HoweverFig 1 SEM microphotographs of fractured surfacesseen in Table 1. thieved a stronger effecthe impact strength than the compatibilizers. For each compo- but also obvious deformation occurred during the fracture(c)sition, the impact strength exhibited a maximum with increas- When both EPDM and y-radiation were employed, the fracing irradiation dose, which occurred around 70 kGy. Under tured surface looked like a homogeneous system(d), and they-radiation, different polymer chains response differently. Itas generally thought that for polyethylene, crosslinking ishe main tendency and for polypropylene, chain scission pIhen a mixture of polyethylene andReferencesolypropylene was subjected to irradiation, the situation may beI Ehring J R. Plastics Recycling Products and Processes, Carldifferent, some polypropylene radicals may combine with polyHanser: New York. 1992thylene ones. For this reason, for moderate dose of irrad2 Poulakis J G. Papaspyrides C D. Adv Poly Technol. 1995(14): 2373 Blom H P, The J W, Rudin A J Appl Polym Sci, 1996(61): 959he crosslinking would be main tendency and at high doses ofTable 1 Impact strength of samples高能辐射与增容剂在混杂聚烯烃回收中的作用研究Irradiation dose/kGElmaghor k张丽叶,励杭泉(北京化工大学材料科学与工PCR/HDPE/EVA程学院,北京10029)在用挤岀机进行混杂聚烯烃回收100/0/0加工过程中,通过加入增容剂,对挤岀共混物进行高能辐0/10/0照。发现适量的γ-射线能够比增容剂更有效地改善体系80/20/0相容性,提高再生材料的冲击强度。辐照强度过高则会产13.888.69生过多断链而使材料韧性下降。关键词聚乙烯聚丙烯71.2/23.8/6.7No breakγ-射线三元乙丙橡胶沖击强度PCR/HDPE/EPDM中国煤化工No break No breakReceivedCNMHG71.2/23.8/6.7No break47.5/47.5/10x To whom all correspondences should be addressed