用于发泡成型的高熔体强度聚丙烯的研究

在同向双螺杆挤出机上,对聚丙烯(PP)进行硅烷交联,制得高熔体强度聚丙烯(HMSPP),然后制备高发泡倍率的PP制品。分析了改性剂用量对PP熔体流动速率、熔体黏度、熔体强度、凝胶含量、力学性能、热性能和发泡性能的影响。结果表明:自制HMSPP的熔体强度和熔体黏度分别是纯PP的5.01倍和1.52倍,力学性能和耐热性与纯PP相比均有较大提高,可用于成型高发泡倍率制品。     

聚丙烯高发泡材料

为提高聚丙烯(PP)的熔体强度,改善PP的发泡性能,用双螺杆挤出机对PP进行硅烷交联改性,制备出了高熔体强度聚丙烯(HMSPP)后,进行了模压法发泡的研究.结果表明:HMSPP随着引发剂含量的增加,改性PP的熔体强度提高;PP发泡材料的密度降低至0.118 g/cm3.发泡剂AC的用量及成核剂的含量对发泡材料的表观密度有很大影响,当发泡剂含量为2.5份、成核剂含量为1份时,得到的PP发泡板材密度降低,发泡倍率增大,泡孔均匀致密,力学性能较好.     

高熔体强度聚丙烯的研制

用过氧化物引发聚丙烯(PP)交联制备高熔体强度聚丙烯(HMSPP),研究了过氧化物的用量、反应温度、螺杆转速对HMSPP性能的影响。得到的HMSPP比普通PP的熔体强度提高约3倍。用所研制的HMSPP进行发泡实验,制得泡孔结构较均匀且闭孔的发泡制品。     

组合发泡剂对聚丙烯发泡行为的影响研究

采用物理发泡剂和化学发泡剂的组合发泡剂对聚丙烯(PP)和高熔体强度聚丙烯(HMSPP)在自制的单螺杆串联单螺杆挤出发泡机组上进行挤出发泡试验。通过真密度计/开闭孔率测定仪和扫描电子显微镜对发泡制品的密度、发泡倍率和泡孔形态进行测试。研究结果表明,采用组合发泡剂后,大部分PP和HMSPP发泡制品的泡孔密度提高,发泡倍率增加,泡孔尺寸分布更加均匀,泡体结构优于单独使用物理发泡剂或化学发泡剂的发泡制品。     

聚丙烯挤出增强结构发泡成型的研究

通过加入高熔体强度聚丙烯(HMSPP)、低密度聚乙烯(LDPE)及(乙烯/丙烯/二烯)共聚物(EPDM)对聚丙烯(PP)进行共混改性,提高其熔体强度;并在此基础上,以玻璃纤维(GF)改性PP母粒对PP进行增强,使用单螺杆挤出机获得了PP挤出增强结构发泡制品.重点分析了PP挤出增强结构发泡中HMSPP、LDPE、EPDM、GF改性PP母粒含量及工艺参数对PP挤出增强结构发泡制品的影响.结果表明,当PP为100份、LDPE为15份、EPDM为5份、GF改性PP母粒为15份,机头温度160℃,螺杆转速20 r/min,机头压力12.5 MPa时,能获得较好的PP增强结构发泡制品.     

原位添加α晶成核剂对高熔体强度聚丙烯性能的影响

采用过氧化苯甲酰(BPO)为引发剂,通过一步反应挤出法将接枝单体苯乙烯(St)和端乙烯基硅油(VS)接枝到等规聚丙烯(i PP)上制备高熔体强度聚丙烯(HMSPP),同时在制备过程中原位添加α晶成核剂S20或NA11,考察了两种不同的α晶成核剂对HMSPP的制备及其结晶性能、力学性能和发泡性能的影响。熔体流动速率和分子量分布的测试结果表明,S20或NA11的原位添加没有影响i PP接枝反应的进行;差示扫描量热研究表明,成核剂的加入可以有效促进HMSPP的成核结晶,消除了HMSPP结晶过程中的双结晶峰现象,但成核剂的加入对HMSPP的力学性能并无显著影响。S20或NA11的加入可以有效调控发泡样品的泡孔尺寸,使得泡孔直径从38μm增大到50μm以上,发泡倍率也分别从25倍增大到36倍和37倍。     

聚丙烯发泡材料的应用及研究进展

综述了聚丙烯(PP)发泡材料的加工方法和主要应用。着重介绍了改善聚丙烯熔体强度的几种方法,特别是高熔体强度聚丙烯(HMSPP)的优点及目前的生产状况。并对聚丙烯发泡的机理和发泡材料的应用进行了论述。     

高熔体强度聚丙烯的研究与应用现状

普通聚丙烯(PP)由于熔体强度低和加工温度范围窄,在热成型、挤出涂布和挤出发泡等领域应用受到限制。高熔体强度聚丙烯(HMSPP)具有较高的熔体强度,使聚丙烯可以在通用设备上熔相热成型、挤出发泡、挤出涂布,从而拓宽了PP应用领域。文章综述了国内外高熔体强度聚丙烯的研究进展和应用现状。     

高熔体强度聚丙烯的制备及性能研究

使用同向双螺杆挤出机,采用普通聚丙烯和过氧化二异丙苯(DCP)以反应挤出交联法制得高熔体强度聚丙烯(HMSPP),并通过正交试验设计进行了配方优化。进一步测试了HMSPP的熔体质量流动速率、凝胶含量、力学性能及热性能,并与普通PP进行了比较。结果表明,制备的HMSPP的凝胶含量、熔体质量流动速率有较大幅度提高,力学和耐热性能比普通PP显著提高,可满足生产可发性聚丙烯泡沫材料的要求。     

高发泡倍率聚丙烯泡沫材料的研制

研究了高熔体强度聚丙烯（HMSPP）／共聚聚丙烯（PP）／低密度聚乙烯共混体系的发泡性能。通过考察不同组分及含量、共混体系的熔体流动速率、熔体强度、储能模量和损耗模量研究体系结构性能间的差异。当m（HMSPP）／m（PP））为7：93时．发泡制品的密度约为0．12g／cm^3,所得制品泡iL尺寸均匀、泡壁薄、外观规整。研究发现．当化学发泡剂含量为2-3质量份、成核剂含量为O．1～0．2质量份时,得到的制品密度较低、泡孔结构规整。     

聚丙烯发泡材料的应用及研究进展

综述了聚丙烯（PP）发泡材料的应用及其发展的优越性,分析了目前PP发泡材料制备过程中存在的问题,指出了改善PP发泡性能的关键是制备高熔体强度聚丙烯（HMSPP）,介绍了国内外HMSPP的制备及其发泡的研究进展,指出硅烷接枝交联改性技术具有成本适中。产品质量好并容易控制的特点,是目前的HMSPP制备技术中最有希望的技术。     

化学改性高熔体聚丙烯的制备及其挤出发泡特性研究

以过氧化二异丙苯(DCP)为交联剂、三烯丙基异三聚氰酸酯(TAIC)为助交联剂,通过平行双螺杆挤出机制备了高熔体强度聚丙烯(HMSPP),研究了DCP用量对PP的流变性能、材料的热性能及发泡特性的影响。结果表明:DCP与TAIC配合使用能有效控制PP交联,从而制得有一定凝胶含量的HMSPP,同时材料的耐热性也得以提高,当DCP用量为0.8份,TAIC为3份时,制备的HMSPP,挤出发泡特性最佳。     

Polydimethylsiloxane assisted supercritical CO2 foaming behavior of high melt strength polypropylene grafted with styrene

Foamable high melt strength polypropylene (HMSPP) was prepared by grafting styrene (St) onto polypropylene (PP) and simultaneously introducing polydimethylsiloxane (PDMS) through?a?one-step?melt extrusion process. The effect of PDMS viscosity on the foaming behavior of HMSPP was systematically investigated using supercritical CO₂ as the foaming agent. The results show that the addition of PDMS has little effect on the grafting reaction of St and HMSPP exhibits enhanced elastic response and obvious strain hardening effect. Though the CO₂ solubility of HMSPP with PDMS (PDMS-HMSPP) is lower than that of HMSPP without PDMS, especially for PDMS with low viscosity, the PDMS-HMSPP foams exhibit narrow cell size distribution and high cell density. The fracture morphology of PDMS-HMSPP shows that PDMS with low viscosity disperses more easily and uniformly in HMSPP matrix, leading to form small domains during the extrusion process. These small domains act as bubble nucleation sites and thus may be responsible for the improved foaming performance of HMSPP.     

Structure and properties of high melt strength polypropylene prepared by combined method of blending and crosslinking

High melt strength polypropylene (HMSPP) was prepared by in situ heat induction reaction, in which pure polypropylene (PP) powders without any additives was used as basic resin, and low density polyethylene (LDPE) and trimethylolpropane triacrylate (TMPTA) were added as blending resin and as crosslinking agent, respectively. Microstructure of the obtained HMSPP (PP/LDPE/TMPTA blends) was characterized by FTIR, Wide‐angle X‐ray diffraction (WAXD), and testing of gel content. The effect of LDPE content on melt strength and melt flow rate of HMSPP were investigated. When the content of LDPE was 40 wt %, the melt strength of the HMSPP was above 16 CN, which was much higher than those of pure PP powder (2.6 CN) and PP/LDPE blends without TMPTA (6.1 CN). Moreover, thermal behavior and mechanical properties of the HMSPP were also investigated. The results showed that the thermal stability and impact strength of HMSPP were greatly improved. In addition, HMSPP possessed good processing performance and good foaming properties. The foams produced by HMSPP showed uniform, closed, and independent cells. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

加工参数及配方对PP/LLDPE共混物泡孔形态的影响

采用高压毛细管流变仪对不同含量碳酸钙(CaCO3)的聚丙烯/线型低密度聚乙烯(PP/LLDPE)共混物的流变性能进行了表征;并利用自制的实验装置,在不同发泡温度和饱和压力下,对共混物进行了超临界CO2模拟挤出发泡实验研究。结果表明:使用高熔体强度聚丙(烯HMSPP)发泡可以获得较好的泡孔形态;添加成核剂CaCO3可以使发泡试样的泡孔结构更加规则,泡孔分布更加均匀;随着CaCO3含量的增加,共混物的稠度上升,非牛顿指数降低,当CaCO3含量为3%时,共混物的发泡效果较好;130℃为最佳发泡温度,此时发泡试样的结构完整尺,寸均匀;随着饱和压力的增加发,泡试样的泡孔密度也有所提高。     

Preparation and foamability of high melt strength polypropylene based on grafting vinyl polydimethylsiloxane and styrene

A novel strategy was developed by melt grafting reaction in the presence of macromonomer vinyl polydimethylsiloxane (VS) and comonomer styrene (St) for preparing high melt strength polypropylene (HMSPP), and the rheological behavior, melt strength, and foaming ability of HMSPP were investigated. The results showed that VS and St were successfully grafted onto isotactic polypropylene (iPP), and the melt strength of HMSPP increased by more than 12 times compared to that of the virgin iPP. Moreover, HMSPP exhibited excellent foaming ability with smaller cell size, higher cell density, and higher expansion ratio compared to the virgin iPP when supercritical carbon dioxide was used as the blowing agent. POLYM. ENG. SCI., 55:251–259, 2015. © 2014 Society of Plastics Engineers     

高熔体强度PP的技术进展

叙述了HMSPP的性能、特点及生产技术进展,并介绍了HMSPP的主要应用。