固态TAIC用量对辐照交联EVA性能的影响

以固态三烯丙基异氰脲酸酯(TAIC)为交联促进剂,通过电子束辐照(辐照剂量120 k Gy)制备了不同固态TAIC添加量的交联型乙烯-醋酸乙烯共聚物(EVA)。着重考察了固态TAIC的添加对交联EVA样品拉伸性能和电性能的影响,并利用扫描电子显微镜(SEM)和傅里叶变换红外光谱(FTIR)对EVA样品进行了表征。结果表明:随着固态TAIC用量的增加,交联EVA样品的断裂伸长率和拉伸强度均呈下降的趋势;随着固态TAIC用量的增加,交联EVA样品的体积电阻不断增大,但当固态TAIC用量超过3 phr后,体积电阻基本保持不变;FTIR分析结果表明,当含有固态TAIC的EVA样品受到辐照时,固态TAIC用量越大,其反应越不完全,进而导致对应EVA交联样品拉伸性能的劣化。     

交联聚乙烯绝缘料用基础树脂的性能研究

利用拉伸试验、红外光谱、凝胶渗透色谱、差示扫描量热法、流变表征等方法测试了交联聚乙烯绝缘料用基础树脂的性能,并研究了制备硅烷交联和过氧化物交联聚乙烯绝缘料的基础树脂组成。结果表明,交联聚乙烯绝缘料用LDPE树脂的基本性能:MFR为2.0g/10 min,密度为0.920g/cm3,熔点为107℃左右,拉伸强度大于12MPa,断裂伸长率大于580%,介电常数小于2.3,相对支化度2.34左右。硅烷交联聚乙烯绝缘料宜用LLDPE和LDPE的共混物做基础树脂,而过氧化物交联聚乙烯绝缘料的基础树脂用LDPE即可。     

电子束辐照交联PVC/EVA共混物的研究

以丙烯酸酯类多官能团不饱和单体为交联敏化剂，采用电子束对聚氯乙烯(PVC)与乙烯—酸酸乙烯共聚物(EVA)的共混物进行辐照交联。研究了VA质量分数、交联敏化剂种类及用量、辐照剂量、EVA用量对共混物凝胶质量分数、力学性能以及热延伸性能的影响。结果表明：EVA共聚物能促进PVC的辐照交联，增加共混体系的凝胶质量分数，改善其力学及热延伸性能；EVA共聚物中VA质量分数增大，共混体系的凝胶质量分数增大，力学及热延伸性能改善更明显。     

ADP/A-SEP复配体系对EVA/MPE线缆复合材料的改性研究

采用乙烯基三乙氧基硅烷(A151)对海泡石(SEP)进行表面处理制得A-SEP,并同二乙基次磷酸铝(ADP)复配用作乙烯-醋酸乙烯共聚物(EVA)/茂金属聚乙烯(MPE)线缆复合材料的阻燃改性剂。考察了ADP/A-SEP复配体系组成对EVA/MPE线缆复合材料拉伸性能、阻燃性能和加工流动性的影响。结果表明,ADP虽能明显改善EVA/MPE线缆复合材料的阻燃性能,但对拉伸性能负面影响较大。A-SEP同ADP具有较好的协效阻燃效果,且能够同时改善EVA/MPE线缆复合材料的拉伸性能。当ADP添加量为25%、A-SEP添加量为3%时,EVA/MPE线缆复合材料的拉伸强度与断裂伸长率分别为11.43 MPa和689%;极限氧指数(LOI)达到32%,初始热降解温度和残炭率分别为352.89℃和5.75%,体积电阻率为2.63×10¹³Ω·cm。此外A-SEP添加量不超过3%时,其对EVA/MPE/线缆复合材料的加工流动性影响不大。     

热塑性EVA半导电屏蔽料的研制

研究了基体树脂、导电材料、润滑剂、抗氧剂对热塑性乙烯-乙酸乙烯共聚物(EVA)半导电屏蔽料性能的影响,确立了EVA半导电屏蔽料配方:EVA100份,导电炭黑55份,润滑剂8.5份,抗氧剂0.80份。对产物性能的表征表明,该半导电屏蔽料20℃时的体积电阻率为48.3Ω·cm,拉伸强度为14.2MPa。     

EVAL-g-MANa离聚物对PP/EVA热塑性硫化橡胶性能的影响

将皂化乙烯-乙酸乙烯共聚物接枝马来酸钠(EVAL-g-MANa)离聚物加入聚丙烯(PP)/乙烯-乙酸乙烯共聚物(EVA)热塑性硫化橡胶中,探讨了EVAL-g-MANa对PP/EVA热塑性硫化橡胶力学性能、加工性能及微观结构的影响。结果表明:EVAL-g-MANa可作为PP/EVA热塑性硫化橡胶的相容剂。当EVAL-g-MANa用量为6 phr时,PP/EVA热塑性硫化橡胶的拉伸强度、悬臂梁缺口冲击强度、弯曲应力分别提高13.79%,23.85%,14.95%,同时,熔体流动速率提高32.56%。     

不同比表面积CCB对EVA/CCB半导电复合材料性能的影响

采用熔融共混法制备了乙烯-醋酸乙烯酯共聚物(EVA)/导电炭黑(CCB)二元复合材料。研究了三种CCB的比表面积、粒径及含量对复合材料的体积电阻率、微观形貌、流变性能和拉伸强度的影响。结果表明,随着CCB含量的增加,EVA/CCB复合材料的体积电阻率下降;其中具有双峰粒径分布且分布范围最宽的CCB填充的EVA复合材料导电性能最佳,CCB(比表面积65 m2/g)质量分数仅为20%时,其体积电阻率为1.2×104Ω·cm,材料由绝缘体转变为半导体。微观形貌结果表明,CCB在EVA基体中的含量越高,CCB粒子之间的间距越小。在EVA中添加CCB会使体系复数黏度和储能模量增大。力学性能测试结果表明,CCB填充EVA树脂使EVA/CCB复合材料的拉伸强度略有下降,断裂伸长率呈下降趋势。     

成瓷助剂对陶瓷化聚烯烃复合材料性能的影响

以乙烯-乙酸乙烯酯共聚物(EVA)和乙烯-1-辛烯共聚物(POE)为基体树脂,低熔点玻璃粉为助熔剂,陶瓷粉为成瓷填料,制备了陶瓷化聚烯烃复合材料,研究了成瓷助剂添加量对复合材料力学性能、电绝缘性能及耐火性能的影响。结果表明：低熔点玻璃粉的加入提高了复合材料的力学性能和击穿场强,体积电阻率略微下降,介电常数变化不大;随着陶瓷粉添加量的增加,复合材料的力学性能先提高后降低,体积电阻率先增大后减小,电气强度提高;成瓷助剂的加入可以提高复合材料燃烧残余物的稳定结构。     

三烯丙基异氰脲酸酯对EVA/LDPE复合材料性能的影响

利用双螺杆挤出机,以乙烯-醋酸乙烯酯共聚物/低密度聚乙烯(EVA/LDPE)为基体,2,5-二甲基-2,5-双(叔丁基过氧基)己烷为引发剂,三烯丙基异氰脲酸酯(TAIC)为交联剂,制备了交联改性的EVA/LDPE复合材料。并通过凝胶含量分析、力学分析、差示扫描分析、动态力学分析以及介电性能测试等,研究了不同添加量的TAIC对该复合材料性能的影响。结果表明:随着TAIC添加量的增加,复合材料的凝胶含量显著提高,可达70%以上;复合材料的拉伸强度则呈现先增大后减小的变化趋势,其中当TAIC添加量为2%时,复合材料的拉伸强度可由添加前的11.64 MPa提高到16.48 MPa。此外,随着TAIC添加量的增加,复合材料的熔点、结晶温度和储能模量下降,玻璃化转变温度、维卡软化温度、黏度升高,介电常数亦呈下降趋势,但介质损耗的变化不大。     

正交试验法制备热塑性低烟无卤阻燃聚烯烃电缆料

用正交试验法研究了不同醋酸乙烯(VA)含量的乙烯-醋酸乙烯共聚物(EVA)的不同配比、氢氧化镁(MH)及滑石粉的用量对以EVA为基础树脂的热塑性低烟无卤阻燃电缆料性能的影响。结果表明:EVA为100phr,表面处理的MH为80phr,滑石粉为20phr时,材料的氧指数达到了43%,拉伸强度为8.3MPa,断裂伸长率为550%,低温冲击脆化温度达到-30℃。满足热塑性低烟无卤阻燃聚烯烃电缆料的性能要求。     

Ethylene‐vinyl acetate copolymer/multiwalled carbon nanotube/organoclay nanocomposites

Ethylene‐vinyl acetate copolymer (EVA) was melt‐mixed with multiwalled carbon nanotubes (MWCNTs) and organoclays, and the effects of simultaneous use of organoclays and MWCNTs on the surface resistivity and tensile properties of EVA nanocomposites were investigated. The surface resistivity of EVA/MWCNT nanocomposite with 1 phr of MWCNT is out of our measurement range (above 10¹² Ω/square). With increasing content of organoclay from 0 to 3 phr, the surface resistivity of the EVA/MWCNT/organoclay nanocomposites with 1 phr MWCNT remains out of our measurement range. However, the surface resistivity of the nanocomposite decreases to 10⁶ Ω/square with addition of 5 phr organoclay. The tensile properties of EVA/MWCNT/organoclay nanocomposites with 1 phr MWCNT and 5 phr organocaly are similar to those of EVA/MWCNT nanocomposites with 5 phr MWCNT except tensile modulus. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers     

Mechanical,Thermal and Electrical Properties of Ethylene Vinyl Acetate Irradiated by an Electron-Beam

The effects of electron beam irradiation of (ethylene vinyl acetate) EVA containing 18% vinyl acetate was studied. The EVA sample was then irradiated by using 3 MeV electron beam machine at doses ranging from 120 to 360 kGy in air at room temperature and analyzed for mechanical, thermal and electrical properties. It was revealed by DSC analysis that the crystallinity of the electron-beam radiated EVA decreased slightly as verified by a marginal reduction in the densities and heats of melting. Thermal degradation of EVA occurred through two steps as shown by the thermogravimetric curve with maximum rates of 350 and 450°C, respectively. The results obtained from both gel content and hot set tests showed that under the irradiation conditions employed, the EVA sample cross-linked by the electron beam irradiation, and the degree of cross-linking in the amorphous regions was dependent on the irradiation dose. A significant improvement in the tensile strength of the neat EVA samples was obtained upon electron-beam radiation up to 210 kGy with a concomitant decline in elongation of break. Various electrical properties of EVA such as surface and volume resistance, breakdown voltage and dielectric constant were studied as a function of radiation dose. It was revealed that the surface resistance and volume resistivity of the EVA reaches a maximum at a 190 kGy dose of radiation. No considerable change of breakdown voltage and dielectric constant was observed with increasing irradiation dose. These studies suggest that radiation-cured EVA is more thermally and mechanically stable than pure EVA. Similarly, the results from the electrical properties revealed that surface and volume resistance are higher than pure EVA.     

Effect of organoclay content on the mechanical properties of ethylene‐vinyl acetate copolymer/ multi‐walled carbon nanotube/organoclay foams

The main objective of this study is to obtain ethylene‐vinyl acetate copolymer (EVA)/multi‐walled carbon nanotube (MWCNT)/organoclay foams with improved mechanical properties without increase of their density, compared with EVA/MWCNT foams. MWCNT content was fixed at 5 phr in this study. To achieve the objective, EVA was melt‐mixed with MWCNTs and organoclays in a bench kneader. And the obtained EVA/MWCNT/organoclay mixtures were mixed with chemical blowing agent and cross‐linking agent in a two roll‐mill. After being mixed in a two roll‐mill, the mixtures were put in a mold and the foams were obtained by compression‐molding. The effect of organoclay content on the mechanical properties and surface resistivity of EVA/MWCNT (5 phr)/organoclay foams was investigated. The addition of 1 phr organoclays to the EVA/MWCNT (5 phr) foams resulted in the improvement of tensile strength, 100% tensile modulus, tear strength, and compression set without increase of the density. However, further increase in content of organoclay (3 phr) leaded to a deterioration of mechanical properties. Therefore, determining the optimal content of organoclay was very important in order to achieve the main objective of this study. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

硅烷交联聚乙烯电力电缆绝缘料的研制

采用两步法制备了硅烷交联聚乙烯（PE）电力电缆绝缘料。以双螺杆挤出机为反应器,以低密度聚乙烯（LDPE）和线型低密度聚乙烯（LLDPE）为基础树脂,考察了影响PE接枝交联的主要因素（如基础树脂的配比,交联剂的用量及种类,引发剂、抗氧剂的用量等）,得出了具有良好性能的硅烷交联PE电力电缆绝缘料的配方（质量份数）：LDPE为85．00phr,LLDPE为15．0H0phr,硅烷W为0．60phr,硅烷Q为1．40phr,引发剂为0．12phr,抗氧剂为0．20phr。     

EVA/硅橡胶共混材料的阻尼性能研究

以甲基乙烯基硅橡胶和乙烯-醋酸乙烯酯共聚物(EVA)为原料,通过熔融共混法制得EVA/硅橡胶共混材料,研究了EVA用量对共混材料力学性能、阻尼性能、热稳定性和拉伸断面形貌的影响。结果表明,随着EVA用量从10份增加到40份,共混材料的拉伸强度从6.6 MPa降至5.1 MPa,撕裂强度从21.9 kN/m降至17.6 kN/m,拉断伸长率从438%升至467%后降至448%,邵尔A硬度从64度升至65度后降至60度,吸收能量从1368 N/mm降至996 N/mm后升至1057 N/mm,损耗角从12.9°升至16.4°后降至15.1°。当EVA用量为30份时,材料的损耗角达到最大值16.4°;EVA的加入在一定程度上降低了材料的热稳定性;EVA与硅橡胶在一定条件下表现出良好的相容性。     

EVA树脂性能及用途

EVA树脂不仅是生产胶粘剂的主要原料之一,而且还可以广泛地应用到其他领域。本文从应用的角度,系统地介绍了EVA树脂的性能——MFR、VA％与分子量、熔融粘度、硬度、弹性系数、抗拉强度、伸长度、环球软化温度、结晶度、玻璃化温度和熔点的关系,以及EVA树脂的主要优点和用途。     

导电炭黑及与沥青基碳纤维并用对NBR导电、导热性能的影响

研究了导电炭黑(VXC72)用量及与沥青基短切碳纤维(CF)并用对丁腈橡胶(NBR)的力学性能及导电、导热性能的影响;并用扫描电镜(SEM)观察填料的分散状态,同时考察了双辊开炼机对CF长径比的剪切破破坏程度。结果表明,随VXC72用量的增加,NBR/VXC72硫化胶的拉伸强度、撕裂强度和导热系数基本呈线性增加;体积电阻率呈阶梯形下降,逾渗阈值为25 phr。随VXC72/CF并用比的增大,NBR硫化胶的拉伸强度和撕裂强度明显降低,体积电阻率略有减小,而导热系数有一定程度的增加。填充20 phr CF时,NBR的导热系数较填充VXC72时提高了约30%。混炼使CF的长径比L/D剧烈降低,由原来的600降低到10-20,这也许是CF对NBR体积电阻率降低幅度不大的主要原因。     

HDPE/PC/EVA共混体系的性能研究

研究了乙烯-醋酸乙烯共聚物(EVA)增容高密度聚乙烯(HDPE)和聚碳酸酯(PC)共混体系，讨论了EVA，PC对HDPE／PC共混合金性能的影响。结果表明：随PC用量的增加，HDPE／PC共混合金的熔体流动速率减小，缺口冲击强度增大，拉伸强度增大，维卡软化点变化不大。EVA能够改善合金体系的加工流动性，却明显降低了合金体系的力学性能。     

永丰超白大方解石粉在ABS中的应用

选取3种不同细度的由永丰超白大方解石制成的超细碳酸钙(CC)(CC–1250,CC–2500,CC–6000CC)作为无机填料,以丙烯腈–丁二烯–苯乙烯塑料(ABS)为基体,采用双螺杆挤出机制备了ABS/CC复合材料,研究了CC的细度和用量对ABS力学性能、熔体流动速率(MFR)和密度的影响。结果表明,在相同的CC(20份)用量下,细度适中的CC–2500在ABS中的分散性最好,由其制备的ABS复合材料具有最好的综合力学性能和加工流动性以及最小的密度。随CC–2500用量的增加,复合材料的拉伸强度和弯曲强度逐渐减小,MFR先增加后降低,密度逐渐增大,而缺口冲击强度总体呈降低的趋势,但在CC–2500用量为20份时有所回升,基本与CC–2500用量为5份时的数值相当。当CC–2500用量为20份时,复合材料的综合性能最好,拉伸强度、弯曲强度、简支梁和悬臂梁冲击强度分别达到37.25 MPa,54.98 MPa,18.42 k J/m~2和22.87 k J/m~2,MFR为12.33 g/10 min,密度为1.081 g/cm~3。扫描电子显微镜结果显示,即使在用量较高的情况下,CC–2500仍可以均匀地分散在ABS基体中。