永久导电辐射交联聚烯烃泡沫塑料的开发与研究

以低密度聚乙烯(LDPE)为主体,超导碳黑为导电填料,偶氮二甲酰胺(AC)为发泡剂,制备了永久导电聚烯烃泡沫材料(IXPE)。对辐射交联聚乙烯发泡材料的导电性能、辐照剂量进行了研究,并对永久导电辐射交联聚乙烯发泡材料的综合性能进行了分析。结果表明,在优选的几种超导碳黑中,当T-1添加50份,辐照剂量为13.5r/min+1.5MeV+15mA+2层时,能得到性能优异的永久导电辐射交联聚烯烃泡沫塑料,体积电阻率可以降到105Ω·cm。     

辐照交联聚烯烃/硅橡胶弹性体性能研究

本文采用高能电子束对聚烯烃/硅橡胶复合弹性体进行辐照交联,通过万能材料试验机及扫描电镜对复合弹性体辐照前后的机械性能及界面形态进行分析。结果表明:复合弹性体的拉伸性能随着辐照剂量的增加呈现先增加后减少的趋势,在辐照剂量为60kGy,辐照交联剂TAIC添加份数为1.8份时,拉伸性能最好;同时,分子量较低,流动性较好的苯基硅橡胶能够更好地实现与聚烯烃弹性体的共混。     

γ射线辐照对PP/PUR-T共混材料性能的影响

利用双螺杆挤出机制备了聚丙烯(PP)/热塑性聚氨酯弹性体(PUR-T)共混材料,研究了这类共混材料经1~25kGy剂量的γ射线辐照前后的力学性能、动态力学行为与形态。发现在空气气氛下经γ射线(尤其是剂量为5kGy)辐照后,PP/PUR-T(85/15)体系的界面粘结得到了明显改善,其拉伸强度、弯曲强度、弯曲弹性模量及缺口冲击强度均比未辐照时有明显提高,表明γ射线辐照对PP/PUR-T共混材料有增容作用。     

NR/LLDPE热塑性弹性体泡沫材料的制备与性能研究

采用化学交联模压法制备天然橡胶/线性低密度聚乙烯（NR/LLDPE）共混型热塑性弹性体泡沫材料。研究了橡塑比、发泡剂用量、硫磺用量以及模压发泡成型压力对泡沫材料的力学性能和相对密度的影响,并对泡沫材料的微观结构进行了荧光显微镜分析。结果表明：橡塑比、发泡剂用量、硫磺用量和压力对材料的性能影响较大,且当橡塑共混比为70/30、发泡剂用量为10 phr、硫磺用量为1.5phr和压力为1 MPa时,可制得密度较低且具有较好综合力学性能的泡沫材料;微观结构表征显示,此条件下制得的泡沫材料的泡孔较小、大小均一、分布均匀且以闭孔为主。     

辐射交联聚乙烯泡沫的研究

通过辐射交联技术制成聚乙烯泡沫 ,研究了辐照剂量、凝胶含量、发泡剂用量、助剂用量、发泡温度、发泡时间对发泡倍数的影响。结果表明 ,辐照剂量 30kGy ,发泡温度 180℃ ,发泡时间 2min可制得发泡倍数 30倍的聚乙烯泡沫。     

聚烯烃对绢云母/三元乙丙橡胶复合材料结构与性能的影响

研究聚烯烃包括聚丙烯、高密度聚乙烯、乙烯-醋酸乙烯酯共聚物和聚烯烃弹性体对绢云母/三元乙丙橡胶复合材料微观结构、物理性能、导热性能和导电性能的影响。结果表明:随着聚烯烃结晶度的增大,复合材料的最大转矩、硫化速率和撕裂强度呈增大趋势,焦烧时间缩短,导热性能提高,导电性能变化不大。     

γ线辐照对PP／PUR-T共混材料性能的影响

利用双螺杆挤出机制备了聚丙烯（PP）／热塑性聚氨酯弹性体（PuR—T）共混材料，研究了这类共混材料经1～25kGy剂量的γ射线辐照前后的力学性能、动态力学行为与形态。发现在空气气氛下经γ射线（尤其是剂量为5kGy）辐照后，PP／PUR-T（85／15）体系的界面粘结得到了明显改善，其拉伸强度、弯曲强度、弯曲弹性模量及缺口冲击强度均比未辐照时有明显提高，表明γ射线辐照对PP／PUR-T共混材料有增容作用。     

辐射交联高发泡聚乙烯泡沫的制备及应用

利用辐射交联技术制备了高发泡的聚乙烯（ＰＥ）泡沫。研究了辐射剂量，发泡剂用量、发发泡时间对发泡倍率的影响。结果表明，辐照剂量为３０ＫＧｙ，发泡温度为２００℃，发泡时间为２ｍｉｎ时能够制备发泡倍率为３０倍的ＰＥ泡沫。     

微孔注塑发泡聚氨酯成型工艺及微观结构研究

采用超临界CO_2微孔注塑成型工艺制备热塑性聚氨酯弹性体(TPU)微孔泡沫材料,研究超临界流体(SCF)注塑发泡工艺对TPU泡沫微观结构及力学性能的影响规律。本文基于正交优化实验设计,以制品拉伸强度为优化指标,优化微孔成型工艺参数。最优微孔注塑工艺为:注射量16 cm~3;SCF含量0.4%;注射速度60 cm~3/s;保压压力1 MPa。本文通过研究成型工艺对制品结构及力学性能的影响,为超临界CO_2制备高发泡率高性能TPU软质泡沫材料提供技术支持。     

舰船用辐射交联无卤阻燃电缆护套料的研究

应用γ射线辐射交联技术,制备出以乙烯－醋酸乙烯/茂金属聚烯烃弹性体/纳米级改性氢氧化铝（EVA/POE/ ATH）为基材的舰船用无卤阻燃电缆护套料,探讨了共混物配比、ATH的种类与用量以及辐射剂量对材料力学性能和阻燃性能的影响。结果表明,随着POE用量的增加,材料的拉伸强度和断裂伸长率增加,耐热老化性能提高,但硬度降低;纳米ATH的加入使材料具有较好的阻燃性能;材料的辐射交联工艺可弥补阻燃剂对材料力学性能的影响,在辐射剂量为80 kGy的条件下,采用EVA /POE/ATH ＝90/10/60（质量份数,下同）的共混体系可制备出综合性能优异的护套料。     

Radiation grafting of methyl methacrylate monomer on natural rubber latex

A method of radiation grafting of methyl methacrylate (MMA) monomer on natural rubber (NR) latex has been studied. The irradiation dose in radiation emulsion polymerization of MMA monomer was lower compared to the irradiation dose for grafting of MMA monomer on NR latex, in order to obtain the same degree of conversion. This is due to the size of the rubber particles which are quite large and, hence, not sufficient to ensure an ideal emulsion polymerization. The irradiation dose for radiation grafting of MMA monomer on latex was around 300 krad to obtain a 75% degree of conversion. However, this irradiation dose was lower compared to the irradation dose for bulk polymerization of MMA monomer, in order to obtain the same degree of conversion. This is due to the gel effect in the viscous media. Radiation grafting of MMA monomer on NR latex does not influence the pH of the latex, but influences the viscosity significantly. The viscosity of the NR latex increased with an increase in irradiation dose, due to the increase of the total solid content in the latex. The MMA monomer converted to P-MMA in NR latex was largely grafted on the NR, or at least insoluble in a solvent for P-MMA, such as acetone or toluene. The hardness of the pure gum vulcanizate with an increase in the degree of grafting or P-MMA content, but the other physical properties, such as tensile strength, modulus, elongation at break, and thermal stability, were not greatly influenced by the degree of grafting.     

Open‐cell polypropylene/polyolefin elastomer blend foams fabricated for reusable oil‐sorption materials

The fabrication of high‐performance oil sorbents is of great significance for oil spill cleanup. The main objective of this study was to prepare open‐cell polypropylene/polyolefin elastomer (PP/POE) blend foams for fabrication of reusable sorbents for oil sorption. Open‐cell PP/POE blend foams were prepared via continuous‐extrusion foaming using supercritical carbon dioxide as the blowing agent. The interconnected open‐cell structure was characterized by scanning electron microscopy. The hydrophobicity and lipophilicity of PP/POE open‐cell foams were revealed by tests of contact‐angle measurement, water and cyclohexane sorption on the foam surface, CCl₄ and cyclohexane sorption in water, and oil/water separation. Further, the sorption tests indicated that PP/POE blend foams showed larger oil‐uptake capacities than pure PP foams. In addition, cyclic compression tests showed that PP/POE open‐cell foams had excellent ductility and significantly improved recoverability compared to pure PP foams. In cyclic sorption–desorption tests, the sorption kinetics was studied in terms of capacity and saturation time, showing that PP/POE foams kept larger sorption capacities for 10 cycles, with larger sorption rates and good reusability. Based on the high open‐cell content, the good hydrophobic and oleophilic properties, the high oil‐sorption capacity, the improved recoverability, the large sorption rate, and the good reusability in cyclic oil‐sorption performance, the PP/POE open‐cell foams have shown promise as potential oil sorbents in applications for oil spill cleanup. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43812.     

The role of nanofillers on (natural rubber)/(ethylene vinyl acetate)/clay nanocomposite in blending and foaming

Nanocomposite foams were fabricated from 60/40 wt% ethylene vinyl acetate (EVA)/natural rubber (NR) blends by using azodicarbonamide as a blowing agent. Two different nanofillers (sodium montmorillonite and organoclay) were employed to study their effects on foam properties. The results were also compared with conventional (china clay)‐filled foams. Transmission electron microscopy, X‐ray diffraction, scanning electron microscopy, and three‐dimensional Microfocus X‐ray computed tomography scanning analysis were performed to characterize the EVA/NR blend morphology and foam structures. The results revealed that the nanofiller acted as a blend compatibilizer. Sodium montmorillonite was more effective in compatibilization, generating better phase‐separated EVA/NR blend morphology and improving foam structure. Higher filler loading increased the specific tensile strength of rubber foams. The rubber nanocomposite foam showed superior specific tensile strength to the conventional rubber composite foam. The elastic recovery and compressive strength of the nanocomposite foams decreased with increasing filler content, whereas the opposite trend was observed for the conventional composite foams with china clay. The thermal conductivity measurement indicated that the nanofiller had better beneficial effect on thermal insulation over china clay filler. From the present study, the nanofillers played an important role in obtaining better blend morphology as compatibilizer, rather than the nucleating agent and the nanofiller content of 5 phr (parts by weight per hundred parts of rubber) was recommended for the production of EVA/NR nanocomposite foams. J. VINYL ADDIT. TECHNOL., 21:134–146, 2015. © 2014 Society of Plastics Engineers     

Effect of gas-phase tortuosity on the mechanical properties of low-density polyolefin open-cell foams at low- and high-strain rates

This paper describes the mechanical behavior in compression, at both low- and high-strain rates, of several low-density open-cell polyolefin-based foams with different gas phase interconnectivities and different levels of gas-phase tortuosity. The mechanical properties of the open-cell polyolefin foams have been compared with two different references: an open-cell low tortuous foam based on flexible polyurethane and closed-cell polyolefin foams. One the one hand, at low-strain rates, it has been observed that the mechanical performance is controlled by the open-cell content and the properties of the polymeric matrix, being the influence of tortuosity small. On the other hand, the influence of the level of tortuosity is critical to high-strain rates. In fact, it has been demonstrated that open-cell polyolefin foams with high tortuosity (HT) present an unexpected mechanical behavior, showing excellent mechanical properties, which are even similar to that of closed-cell polyolefin materials with the same chemical composition. Therefore, low-density polyolefin foams with HT have a unique mechanical performance strongly influenced by the strain rate. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48468.     

天然橡胶发泡材料的压缩行为与能量吸收特性

用发泡剂N,N′-二亚硝基五次甲基四胺(简称发泡剂H)制备了天然橡胶(NR)发泡材料,研究了不同密度的NR发泡材料的压缩行为和能量吸收特性。结果表明,随着发泡剂H用量的增加,NR发泡材料的密度与硬度均降低;NR发泡材料的压缩应力-应变曲线有2个阶段:线性弹性阶段和致密化阶段;随着发泡材料密度的减小,线性弹性区变宽,相对弹性模量降低。在应力较小的时候,密度小的NR发泡材料吸收能量较多,在应力较高的时候,密度大的NR发泡材料吸收能量多。随着发泡材料密度的减小,其吸能效率最大值与理想参数最大值提高。     

Radiation vulcanization of natural rubber with polyfunctional monomers

This study presents the effect of the polyfunctional monomers (PFMs) triallylcyanurate (TAC), triallylisocyanurate (TAIC), trimethylolpropane trimethacrylate (TMPT), ethylene glycol dimethacrylate (EDMA) and zinc diacrylate (ZDA) on the mechanical properties of natural rubber (NR) crosslinked by electron beam (EB) processing. Dependence of mechanical properties and crosslink density on irradiation dose was determined from a dose range of 50 to 200 kGy. The control blends, obtained with benzoyl peroxide as curing agent, were prepared by blending on a laboratory roller and the control sample curing was accomplished on hydraulic press at 160 °C. The results showed an increase in mechanical properties and crosslink density due to the introduction of PFMs. Also, based on the comparison between EB irradiation and dibenzoyl peroxide vulcanization efficiency, the experimental results show that EB irradiation gave the best results.     

辐照交联中密度聚乙烯中空纤维管的结构与性能

研究了加工条件对辐照交联中密度聚乙烯中空纤维管凝聚态结构和力学性能的影响,特别是辐照剂量与中空纤维管抗拉性能和耐扩张性能的关系,并研究了中空纤维管的交联度、结构、晶形和热性能。结果表明:辐照交联聚乙烯中空纤维管的结构和性能可以通过辐照工艺来调控,辐照剂量升高,中空纤维管的凝胶含量提高,抗拉强度增加。     

Effect of Gamma and UV Radiation on Properties of EPDM/GTR/HDPE Blends

Ethylene propylene dine monomer (EPDM) was blended with both ground tire rubber (GTR) and high-density polyethylene (HDPE) prepared at different ratios and then exposed to gamma and ultraviolet radiations. The mechanical, physical, and thermal properties were investigated with respect to the kind of irradiation and blend compositions. A scanning electron microscope was also used to examine the morphology of the irradiated blends. The blend of ratios (75/25/50) exhibited the best mechanical and physical properties after gamma irradiation, so this blend was taken as an example to be exposed to the UV radiation. The results indicated an improvement in the mechanical and physical properties for the blends exposed to gamma irradiation, but the mechanical and physical properties examined after UV irradiation were slightly affected. Scanning electron microscope measurements indicated the improvement in the homogeneity and the compatibility after irradiation, particularly in case of gamma radiation.     

不同发泡剂及工艺条件对BR／SBR／NR发泡材料相结构及尺寸稳定性的影响

分别采用一段和两段模压法制备了以顺丁橡胶（BR）／丁苯橡胶（SBR）／天然橡胶（NR）为基体的橡胶发泡材料,研究了三种化学发泡剂N,N＇-二甲基戊次甲基四胺（H）、4,4＇-氧代双（苯磺酰肼）（OBSH）以及H／OBSH（质量比1：1）复配对发泡及硫化特性的影-向,以及3种发泡剂和2种成型工艺对收缩率及相结构的影响。结果表明,发泡剂H对硫化性能影响最大,含发泡剂H的混炼胶在分解过程中释放的热量最多;加入3种发泡剂都具有一种较大的泡孔镶嵌在较小的泡孔丛中的泡孔形态;密度和线收缩率均随着时间的增加而增加,经H／OBSH复配的发泡剂更适合该体系成型,材料线收缩率均比单独使用H和OBSH小,两段模压法可以有效地提高发泡材料的尺寸稳定性,收缩率降低至3．88％,同时发泡剂使用率最多可提高31．67％。