氢氧化镁粒径对其填充三元乙丙橡胶复合材料力学性能和阻燃性能的影响

分别以粒径为100nm,6．29,3．57,2．92μm的氢氧化镁为阻燃剂和增强剂,加入到100份(质量)三元乙丙橡胶中,考察了填料粒径时复合材料力学性能和阻燃性能的影响。结果表明,随着氢氧化镁粒径的减小,复合材料的力学性能逐渐提高,纳米复合材料的力学性能远优于微米复合材料的。采用锥形量热仪和氧指数仪研究了复合材料的阻燃性能,发现对于未改性氢氧化镁填充体系,随着粒径的减小,复合材料的最大热释放速率降低,引燃时间增长。氢氧化镁经过硅烷偶联剂(Si 69)改性后,纳米复合材料的力学性能显著提高,最大热释放速率和引燃时间变化不大;而微米复合体系的力学性能和阻燃性能都无明显变化。     

动态硫化法制备三元乙丙橡胶/聚酰胺热塑性弹性体

采用动态硫化技术制备了三元乙丙橡胶(EPDM)／聚酰胺(PA)热塑性弹性体,研究了增容剂种类及用量、硫化体系及其用量、加料顺序、PA用量对其性能的影响,用扫描电镜分析了其相态结构。结果表明,用13份(质量份,下同)的氯化聚乙烯作为增容剂时,对该共混体系的增容效果最好;硫黄硫化体系是EPDM／PA热塑性弹性体的最佳硫化剂,当硫黄用量为2份时,既保证了该热塑性弹性体中的橡胶相能充分交联,又可避免过硫化对产品性能造成的负面影响;PA用量为35份的EPDM／PA热塑性弹性体具有良好的力学性能、耐溶剂性能和耐热老化性能;EPDM以平均粒径为2～5μm的粒子形态均匀分布于PA连续相中。     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

团状模塑料/三元乙丙橡胶共混物的表征及其性能的影响因素

用团状模塑料(DMC)与三元乙丙橡胶(EPDM)共混,以EPDM为连续相、DMC为分散相,制备了DMC/EPDM共混物,并对其微观结构进行了表征,研究了DMC与EPDM的质量比、过氧化物硫化荆的种类和用量以及白炭黑的用量对共混物性能的影响.结果表明,DMC和EPDM的界面作用强,相容性好;过氧化苯甲酰(BPO)作硫化荆要好于用过氧化二异丙苯;当DMC与EPDM的质量比为90/100、BPO为5份、白炭黑为50份时,共混物的力学性能和耐热老化性较好.     

不同硫化体系对三元乙丙橡胶物理机械性能和电绝缘性的影响

分别采用硫黄硫化、半有效硫化、硫载体硫化、有机过氧化物硫化和复合硫化体系制备三元乙丙橡胶(EPDM)硫化胶,并考察了不同硫化体系对EPDM硫化胶的硫化特性、物理机械性能与电绝缘性的影响.结果表明,EPDM硫化胶交联结构中,过氧化物硫化的EPDM硫化胶具备优异的电绝缘性,但物理机械性能较差;而硫黄硫化的EPDM硫化胶的物...     

动态硫化对三元乙丙橡胶/聚丙烯共混体系等温结晶行为和形态结构的影响

研究了三元乙丙橡胶/聚丙烯(EPDM/PP)共混物和动态硫化EPDM/PP热塑性弹性体(TPV)的等温结晶行为及形态结构,并用Avrami方程对其进行等温结晶动力学分析。结果表明,EPDM/PP共混物和EPDM/PP TPV的等温结晶行为符合Avrami方程,在相同的结晶温度下,TPV比共混物的Avrami指数小,半结晶时间短,结晶速率常数大;EPDM/PP共混物为双连续相结构,而EPDM/PP TPV是以硫化的细小橡胶颗粒为分散相、PP为连续相的"海-岛"结构,橡胶颗粒尺寸约为0.5μm。     

Recycling of ethylene propylene diene monomer (EPDM) waste. III. Processability of EPDM rubber compound containing ground EPDM vulcanizates

The rheological behavior of ethylene propylene diene monomer (EPDM) compounds containing ground EPDM waste (W‐EPDM) of known composition was studied by using a Monsanto processability tester in a temperature range of 90–110°C and a shear rate range of 306.7–1533.24 s^?1. It is found that the shear viscosity decreases slightly with increasing W‐EPDM loading because of wall slip that results from the migration of lubricants from the W‐EPDM. The addition of W‐EPDM to raw EPDM results in a decreased die swell at all temperatures and shear rates. SEM photomicrographs of the EPDM extrudate surface show improved surface smoothness and reduced extrudate distortion when EPDM is blended with W‐EPDM. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2204–2215, 2003     

超细全硫化粉末丁苯橡胶/三元乙丙橡胶共混物的结构与性能

制备了超细全硫化粉末丁苯橡胶(UFPSBR)/三元乙丙橡胶(EPDM)共混物,研究了其硫化特性、相态结构、动态力学性能及物理机械性能。透射电镜观察表明,无论UFPSBR与EPDM共混比如何,UFPSBR粒子始终保持为分散相。当UFPSBR用量为10份(质量)时,它在EPDM中的分散相尺寸为200 nm左右;用量较高时其分散相尺寸较大,存在大量的聚集体。动态力学分析结果显示共混物存在2个玻璃化转变温度,说明共混物存在两相结构。加工性能分析结果表明,UFPSBR粒子在EPDM基质中形成了网络结构,对EPDM基质起到了较好的增强作用,当UFPSBR与EPDM的质量共混比为50/50时,共混物的拉伸强度可达13.4 MPa。UFPSBR对EPDM的硫化特性有明显影响。     

Effect of treated mica on rheological,cure, mechanical,and dielectric properties of ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO3)/mica

In this study, mica, treated by three types of coupling agents, isopropyl trioleic titanate (NDZ105), 3‐aminopropyltriethoxysilane (KH550), and vinyltrimethoxysiloxane homopolymer (SG‐Si6490), were utilized to improve the properties of ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO₃) composites. It is found that the addition of untreated mica can increase the complex viscosity, while the KH550 modified mica can reduce the complex viscosity. Compared to single usage of coupling agent SG‐Si6490, the hybrid usage of KH550 and SG‐Si6490 can further increase the tensile strength of EPDM/BaTiO₃/SG‐Si6490 treated mica (70/20/10) from 9.10 to 11.01 MPa (22% increase). The untreated mica can increase the interfacial polarity and improve the dielectric constant of EPDM/BaTiO₃ (70/30) from 7 to 9 at 40 MHz (28% increase). Moreover, the KH550 treated mica can enhance the thermal conductivity of EPDM/BaTiO₃ (70/30) from 0.323 W m^?1 K^?1 to 0.446 W m^?1 K^?1 (38% increase). In the meantime, the increased crosslink density caused by coupling agents can increase the volume resistivity of EPDM composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44833.     

环氧化天然橡胶共交联改性EPDM/NR共混物的性能

将三元乙丙橡胶(EPDM)与环氧化天然橡胶(ENR)共交联改性后,再与天然橡胶(NR)共混,考察了ENR共交联改性EPDM/NR共混胶的硫化特性、硫化胶的物理机械性能、溶胀指数和耐热空气老化性能,并对该硫化胶进行了差示扫描量热分析。结果表明,EPDM经过ENR共交联改性后与NR共混,ENR共交联改性EPDM/NR共混胶的交联程度明显提高,各相达到了同步交联,硫化胶的综合性能得到了显著改善。     

三元乙丙橡胶接枝马来酸酐及其在尼龙6中的应用

分析了在含有适量聚丙烯(PP)的三元乙丙橡胶(EPDM)熔融接枝马来酸酐(MAH)反应体系中,引发剂过氧化二异丙苯(DCP)、MAH用量对产物接枝率和流变性能的影响,考察了二甲基苯胺(DMBA)、二甲基甲酰胺(DMF)、硫代二丙酸二月桂酯(DLTDP)3种阻交联剂对接枝反应体系的影响,并研究了尼龙6(PA6)/(EPDM/PP)-g-MAH共混物的微观结构与性能。结果表明:当DCP的质量分数为0·08%、MAH的质量分数为1·2%时,产物的接枝率可达到1·0%左右;在相同条件下,3种阻交联剂对产物的接枝率都有不同程度的降低,而加入DMBA最大程度地降低了体系的交联度;接枝物(EPDM/PP)-g-MAH以较小的粒径均匀分布在连续相PA6中;当(EPDM/PP)-g-MAH质量分数为15%~20%时,共混物发生由脆到韧的转变;当(EPDM/PP)-g-MAH质量分数为25%时,共混物的综合力学性能达到最佳;同时,接枝物的加入增大了共混物中PA6的结晶难度。     

Mechanical property and morphology comparison between the two blends poly(propylene)/ethylene‐propylene‐diene monomer elastomer and poly(propylene)/maleic anhydride‐g‐ethylene‐propylene‐diene monomer

The comparison of the mechanical properties between poly(propylene)/ethylene‐propylene‐diene monomer elastomer (PP/EPDM) and poly(propylene)/maleic anhydride‐g‐ethylene‐propylene‐diene monomer [PP/MEPDM (MAH‐g‐EPDM)] showed that the latter blend has noticeably higher Izod impact strength but lower Young's modulus than the former one. Phase morphology of the two blends was examined by dynamic mechanical thermal analysis, indicating that the miscibility of PP/MEPDM was inferior to PP/EPDM. The poor miscibility of PP/MEPDM degrades the nucleation effectiveness of the elastomer on PP. The observations of the impact fracture mode of the two blends and the dispersion state of the elastomers, determined by scanning electron microscopy, showed that PP/EPDM fractured in a brittle mode, whereas PP/MEPDM in a ductile one, and that a finer dispersion of MEPDM was found in the blend PP/MEPDM. These observations indicate that the difference in the dispersion state of elastomer between PP/EPDM and PP/MEPDM results in different fracture modes, and thereby affects the toughness of the two blends. The finer dispersion of MEPDM in the blend of PP/MEPDM was attributed to the part cross‐linking of MEPDM resulting from the grafting reaction of EPDM with maleic anhydride (MAH) in the presence of dicumyl peroxide (DCP). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2486–2491, 2002     

Stearic acid surface modifying Mg(OH)2: Mechanism and its effect on properties of ethylene vinyl acetate/Mg(OH)2 composites

In this article, FTIR spectra and ESEM images were employed to evaluate the effect of stearic acid surface modification of Mg(OH)₂. As a result, the absorbing peak intensity of organic group on Mg(OH)₂ increased with the coating amount of stearic acid increasing and there was no so‐called surface saturation as expected. The results indicated stearic acid surface treatment of Mg(OH)₂ belonged to the acid–base reaction between stearic acid and Mg(OH)₂, and it would not stop until Mg(OH)₂ was reacted completely. In addition, stearic acid surface treatment of Mg(OH)₂ had remarkable influence on the properties of ethylene vinyl acetate/Mg(OH)₂ composites. With the increasing coating amount of stearic acid, the composites had decreased tensile strength, increased elongation at break, and deteriorated flame retardancy, compared with the composites filled with the uncoated Mg(OH)₂. However, stearic acid surface treatment of Mg(OH)₂ benefited processing ability of composites, and the composites had better processing ability as the coating amount of stearic acid increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

PP/Al(OH)_3/Mg(OH)_2复合材料的导热性能

制备了PP（聚丙烯）/Al(OH)₃/Mg(OH)₂导热复合材料,并用稳态平板导热系数测试仪在不同测试温度下测定该复合材料的导热系数。结果表明,加入Al(OH)₃和Mg(OH)₂使PP导热系数提高。复合材料的导热系数随着填料含量的增加而非线性提高,随着测试温度的升高而非线性提高,随着填料粒径的增大而非线性增大。     

Effects of poly(ethylene‐co‐propylene) elastomer on mechanical properties and combustion behaviour of flame retarded polyethylene/magnesium hydroxide composites

Magnesium hydroxide‐based halogen‐free flame retarded linear low density polyethylene composites containing poly(ethylene‐co‐propylene) elastomer were prepared in the melt process and subsequently vulcanized thermally. Influences of the elastomer on the mechanical properties, combustion characteristics and crystallization behaviour of polyethylene/magnesium hydroxide composites have been investigated. The results from the mechanical tests show that the incorporation of a suitable amount of elastomer into polyethylene/magnesium hydroxide composites after vulcanization can increase both the tensile strength and elongation greatly, compared with those of the composites without the elastomer. It has been found that the properties such as limiting oxygen index, UL‐94 rating, the time to ignition and the rate of heat release of polyethylene/magnesium hydroxide/elastomer composites are all improved in comparison with polyethylene/magnesium hydroxide composites at the same retardant level. Scanning electron microscopy studies show that the incorporation of the elastomer into polyethylene/magnesium hydroxide composites improves the compatibility between the filler and the polymer substrate. The degrees of crystallinity of polyethylene/magnesium hydroxide/elastomer composites decrease with increasing the elastomer content. © 2002 Society of Chemical Industry     

PMMA/粉煤灰/Mg(OH)2复合材料的阻燃隔热性能研究

以粉煤灰为功能填料、氢氧化镁\[Mg(OH)2\]为阻燃剂、甲基丙烯酸甲酯（MMA）为聚合单体、过氧化二苯甲酰（BPO）为引发剂,采用梯度温度本体聚合工艺制备了聚甲基丙烯酸甲酯（PMMA）/粉煤灰/Mg(OH)2复合材料,通过扫描电子显微镜测试了复合材料的微观形貌,并研究了其燃烧性能和隔热性能。研究发现,复合材料中Mg(OH)2添加量为35 份（质量份数,下同）时,阻燃级别为HB级;粉煤灰的添加量为60～80份时,复合材料制得的板材厚度≤20 mm时,隔热效果好。     

Poly(propylene)/poly(ethylene terephthalate‐co‐isophthalate) blends and glass bead filled composites: Microstructure and thermomechanical properties

Blends of poly(propylene) (PP) and poly(ethylene terephthalate‐co‐isophthalate) (co‐PET) (95/5) with and without compatibilizing agent (maleic anhydride PP), as well as composites of these blends with glass beads (50 wt%) with and without silane coupling agent surface‐treatment, were prepared and studied on a basis of the material microstructure and thermomechanical properties. Infrared and Raman spectroscopy, as well as transmission electron microscopy, displayed evidence of MAPP compatibilizing action for the blend. Differential scanning calorimetry showed a remarkable effect of nucleation rate increase exerted by co‐PET on the PP crystallization. Moreover, glass beads were found to increase the PP nucleation rate slightly. PP crystallinity hardly varied with the composition. Wide angle X‐ray diffraction allowed determination of differences in the orientation of the poly(propylene) b‐axis, with more homogeneous orientations in the presence of both co‐PET and glass beads. MAPP promoted the PP b‐axis orientation. Differences in PP α′ relaxation could be analyzed through dynamic‐mechanical thermal analysis (DMTA). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1841–1852, 2004     

Research on the related properties of EVM/Al(OH)3/SiO2 composites applied for halogen‐free flame retardant cable insulation and jacket

The halogen‐free flame retardant (HFFR) ethylene‐vinyl acetate copolymer (EVM)/ATH/SiO₂ composites have been prepared by melting compounding method, and the flame retardant, thermal stability, rheological, electrical, and mechanical properties have been investigated by cone calorimeter, LOI, UL‐94, TG, FE‐SEM, rotational rheometer, dielectric breakdown, and ultimate tensile. The results indicate that the flame retardant of EVM vulcanizates is improved and the fire jeopardizing is dramatically reduced due to the addition of ATH. It is necessary that sufficient loading of ATH (≥120 phr) is needed to reach essential level (LOI > 30; V‐0 rating) of flame retardant for HFFR EVM/ATH/SiO₂ composites used as cable in industry. The rheological characteristics show that at all the measurement frequencies, the storage and loss modulus of the composites increase monotonously as the concentration of ATH filler increases, while the complex viscosity and tan delta present reverse trend. And also, it has been found that the HFFR composites at high filler concentrations still keep good mechanical and electrical properties, which is very important for practical applications as cable. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Determination methods of the grafting yield in glycidyl methacrylate‐grafted ethylene/propylene/diene rubber (EPDM‐g‐GMA): Correlation between FTIR and 1H‐NMR analysis

A normalized and universally applicable calibration function for the Fourier‐transformed infrared (FTIR) quantification of the glycidyl methacrylate (GMA) grafting yield in polymers of known compositions having ethylene block sequences was established. The ¹H nuclear magnetic resonance (¹H‐NMR) spectroscopy results achieved on different GMA‐grafted ethylene/propylene/diene rubber (EPDM‐g‐GMA) and ethylene/GMA copolymers were correlated to their FTIR data to calibrate the relative determination of the FTIR method. Both direct and indirect standardization approaches were followed and evaluated. The calibration deduced was used to investigate the free radical grafting reaction of GMA on EPDM rubber in the melt phase. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2616–2624, 1999     

Mg(OH)_2/红磷复配阻燃NR/LLDPE TPV的研究

研究了硅烷偶联剂KH-550和甲基丙烯酸缩水甘油酯/苯乙烯/过氧化二异丙苯(GMA/St/DCP)多单体"原位"增容改性Mg(OH)2/红磷复配阻燃剂对天然橡胶/线性低密度聚乙烯动态硫化热塑性弹性体(NR/LLDPE TPV)的阻燃效果、静态和动态力学性能及耐热分解性能的影响。结果表明,"原位"增容改性有利于改善NR/LLDPE TPV的阻燃性能和力学性能;当m[Mg(OH)2]/m(红磷)=80/8时,"原位"增容改性阻燃NR/LLDPE TPV的氧的最低浓度(LOI)达到25.6%(体积分数),燃烧时无黑烟和熔滴滴落现象,力学性能保持率较高并具有较好的耐寒性和耐热分解性能。