共查询到20条相似文献,搜索用时 67 毫秒
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通过乳液接枝聚合法合成丙烯腈-丁二烯-苯乙烯共聚物(ABS)接枝粉料,与苯乙烯-丙烯腈共聚物(SAN)树脂熔融共混得到ABS树脂。探究丙烯腈含量对ABS树脂性能的影响。结果表明:随着丙烯腈含量增加,ABS树脂的拉伸强度、冲击强度、耗散因数、体积电阻率、维卡软化温度以及两相之间相容性上升,但熔体流动速率、表面电阻率、介电常数下降。 相似文献
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针对丙烯腈-丁二烯-苯乙烯(ABS)树脂中的橡胶粒子相形态难以精确调控的问题,提出采用可逆加成断裂链转移(RAFT)乳液聚合合成苯乙烯-丙烯腈无规共聚物和苯乙烯-丙烯腈/丁二烯嵌段共聚物,并通过共混制备嵌段型ABS树脂,研究嵌段共聚物分子结构对材料相形态和机械性能的影响。结果表明,通过乳液共混可制得橡胶粒子均匀分散的ABS树脂,与市售产品相比,采用两嵌段共聚物为增韧剂的嵌段型ABS树脂具有优异的综合性能,将增韧剂改为三嵌段共聚物,材料的拉伸断裂韧性能进一步提升,但缺口冲击性能下降明显。 相似文献
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耿丽丽;任亮;韩业;张明耀;张会轩 《中国塑料》2011,25(3):29-33
采用种子乳液聚合方法,合成一系列苯乙烯-丙烯腈共聚物接枝聚丙烯酸丁酯(PBA-g-SAN)核壳接枝共聚物,将其与苯乙烯-丙烯腈共聚物(SAN树脂)熔融共混,制得ASA树脂,使用动态力学分析仪和扫描电子显微镜考察了扩径中接枝剂的含量和PBA橡胶粒径对ASA树脂性能的影响。结果表明,随着接枝剂含量的增加,PBA-g-SAN接枝共聚物的接枝率升高,当接枝剂占单体BA的3%时,ASA树脂的冲击强度达到110 J/m。ASA树脂的冲击强度随着橡胶粒径的增加先升高后降低。PBA-g-SAN接枝共聚物中PBA的玻璃化转变温度((Tg)随着接枝剂含量的增加而升高,随着PBA橡胶粒径的增加先降低后升高。当PBA橡胶粒径为92.7 nm时,橡胶粒子发生聚集,其他粒径的PBA橡胶均可较好地分散在基体中。 相似文献
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采用湿法挤出工艺,即将乳液聚合合成的丙烯腈-丁二烯-苯乙烯(ABS)接枝共聚物经凝聚和过滤后得到的ABS接枝共聚物湿粉料与苯乙烯-丙烯腈共聚物(SAN)以一定的比例投入湿法挤出机内挤出造粒,直接获得了ABS树脂。考察了ABS接枝共聚物湿粉料含水量、ABS树脂中橡胶含量、抗氧剂含量、挤出机温度及螺杆转速等因素对ABS树脂力学性能的影响。结果表明,挤出温度过高明显引起物料降解,ABS树脂的冲击强度减小,拉伸强度降低;ABS接枝共聚物湿粉料含水量对ABS树脂的性能没有明显影响;透射电子显微镜分析表明,橡胶粒子在SAN基体中分散均匀;湿法挤出的最佳工艺参数为,挤出温度:180℃,螺杆转速:200 r/min,抗氧剂含量:0.154%(质量分数,下同)。 相似文献
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将苯乙烯-丙烯腈共聚物接枝聚丁二烯(PB-g-SAN)与苯乙烯-丙烯腈共聚物(SAN)树脂按照一定比例熔融共混制备具有不同橡胶含量的丙烯腈-丁二烯-苯乙烯共聚物(ABS)树脂。研究了不同橡胶含量对ABS树脂的冲击以及拉伸行为的影响,并通过透射电子显微镜研究了ABS树脂的微观形态及形变机理。结果表明,ABS材料的冲击强度随着橡胶含量的增加先升高后降低;断裂伸长率随着橡胶含量的增大而增大;当橡胶含量较少时,橡胶粒子在基体相中发生聚集现象的可能性较小,分散性较好;随着橡胶含量的增加发生聚集现象的可能性增加,粒子分散性变差;随着橡胶粒子含量的增加,ABS树脂的主要增韧机理是由空洞化到银纹再到剪切屈服的转变。 相似文献
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以正丁基锂为引发剂、环己烷为溶剂、四氢呋喃为调节剂,在模试装置上合成了丙烯腈-丁二烯-苯乙烯(ABS)树脂改性用橡胶——丁苯嵌段共聚物,研究了反应温度与产品支化结构含量、相对分子质量与产品门尼黏度、凝胶质量分数、微观结构含量的关系。结果表明,随着聚合反应最高温度的升高,共聚物支化结构含量增大;当引发温度为55℃、反应最高温度为110~120℃时,产品支化结构含量约为5%,分子量分布约为1.12,其凝胶质量分数、微观结构含量与目标产品一致,丁苯嵌段共聚物的各项性能实测值符合ABS树脂改性用胶要求。 相似文献
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SAN树脂的相对分子质量对ABS树脂力学性能的影响 总被引:1,自引:0,他引:1
通过将三种不同相对分子质量的SAN树脂与同一种ABS接枝粉料进行熔融共混 ,测试共混物的力学性能 ,比较了三种SAN各自的增韧特性。实验结果表明 :SAN树脂的相对分子质量越高 ,制得的ABS树脂的冲击强度和断裂伸长率越高。SAN树脂的相对分子质量对ABS树脂的拉伸强度没有影响。SAN树脂的低聚物和挥发成分对拉伸强度影响较大。将高相对分子质量SAN和低相对分子质量SAN按不同比例混合后 ,再与ABS接枝粉料以 18份橡胶共混 ,考察了高相对分子质量SAN的加入对共混物冲击强度和熔体流动速率的影响。在SAN树脂中加入高相对分子质量SAN树脂后 ,可以提高ABS树脂的冲击强度 ,显著降低加工流动性 相似文献
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Nor Hafizah Ab. Wahab Nor Yuziah Mohd Yunus Zaidon Ashaari Adrian Choo Cheng Yong Nor Azowa Ibrahim 《The Journal of Adhesion》2013,89(3):210-229
The present work evaluates curing and the thermal behavior of different molecular weight phenol formaldehyde (PF) resins used to prepare PF prepreg oil palm stem veneers. The physical properties (solid contents, gelation time, pH, and viscosity) of PF resins were determined. The molecular weight of resins was characterized by gel permeation chromatography, whilst thermal properties were determined by differential scanning calorimetry and thermogravimetric analyses. The average molecular weight of PF resins were 526 g/mole (low), 1889 g/mole (medium), and 5178 g/mole (control - commercial). Among the resins, medium (MMwPF) gives better thermal stability with a retained weight of 48.9% at 300°C. High (Commercial PF) had a low decomposition temperature (109.3°C) which occurred within 11 min. Both low (LMwPF) and MMwPF started to melt at ≥120°C. Based on strength and shear values, phenolic prepreg palm veneers can be prepared using either low or medium molecular weight PF but with varying results. In all cases, the mechanical properties of palm plywood made from PF prepreg veneers were superior to those made from PF-bonded plywood using the commercial process. 相似文献
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通过差示扫描量热仪、高温凝胶渗透色谱仪、旋转流变仪表征了2种具有不同力学性能的双峰高密度聚乙烯薄膜树脂(FHM 9455F1-A、FHM 9455F1-B)结构的差异性,FHM 9455F1-A比 FHM 9455F1-B具有更高的冲击强度和拉伸强度。结果表明,FHM 9455F1-A高相对分子质量部分的相对含量更大,片晶间能够形成更多的系带分子,改善了材料的冲击强度,而片晶厚度,特别是厚片晶部分的片晶厚度更厚,使得材料具有更高的拉伸强度。 相似文献
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采用两段淤浆聚合工艺合成了由低摩尔质量的均聚物和高摩尔质量的共聚物组成的、具有宽峰或双峰摩尔质量分布的高密度聚乙烯大型中空容器级树脂。通过调节第一段和第二段聚合过程中聚合物的熔体质量流动速率来控制摩尔质量的大小及其分布;采用控制第二段共聚物中共聚单体数量来调节聚合物密度;控制第一段小分子数目,增加第二段摩尔质量或调整密度获得最大耐环境应力开裂性(ESCR)。随着共聚单体丁烯-1加入量的增加,反应釜共混物的密度、熔点、结晶度、拉伸屈服应力、断裂伸长率减少。随着高摩尔质量共聚物的含量增加,屈服应力、熔点、密度、结晶度减少,摩尔质量分布的双峰特性也增加,反应釜共混物的均聚物峰的高度减少,共聚物峰的高度增加。流变性能结果表明,通过改变共混物的组分可以获得力学性能和加工性能的平衡。 相似文献
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《国际聚合物材料杂志》2012,61(7):520-531
A new curing agent based on palmitoleic acid methyl ester modified amine (PAMEA) for epoxy resin was synthesized and characterized. Diglycidyl ether of bisphenol A (DGEBA) epoxy resins cured with different content of PAMEA along with diethylenetriamine (DETA) were prepared. The mechanical properties, dynamic mechanical properties, thermal properties, and morphology were investigated. The results indicated that the PAMEA curing agent can improve the impact strength of the cured epoxy resins considerably in comparison with the DETA curing agent, while the modulus and strength of the cured resin can also be improved slightly. When the PAMEA/epoxy resin weight ratio is 30/100, the comprehensive mechanical properties of the cured epoxy resin are optimal; at the same time, the crosslinking density and glass transition temperature of the cured epoxy resin are maximal. 相似文献
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研究了不同生产方法糊树脂制备的聚氯乙烯(PVC)溶胶,在旋转流变仪程序升温模式下的流变性能。通过扫描电子显微镜、激光粒度仪和凝胶渗透色谱仪研究了PVC糊树脂的颗粒形貌、粒度及分布以及相对分子质量及相对分子质量分布特征,从而建立了PVC溶胶流变性能参数与糊树脂特性参数间的关系。结果表明,随着温度的升高,PVC溶胶的储能模量、损耗模量和复数黏度等流变参数呈非正态分布变化趋势,可分为4个阶段:前三阶段,流变参数先降低,后由缓慢升高至急速升高,形成一个肩峰并达到一个最大值,黏度变化趋势与树脂颗粒形态有关;第四阶段,流变参数逐步变小,黏度主要受树脂相对分子质量及相对分子质量分布的影响。 相似文献
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The effect of some types of xylene formaldehyde on epoxy resin adhesive is studied. Xylene formaldehyde resin or modified xylene formaldehyde resins are mixed into liquid epoxy resin and curing properties of the blends, their adhesive properties and the dispersion state of xylene formaldehyde resin in cured adhesive film are examined. The results obtained are as follows.
1) Generally, by the addition of xylene formaldehyde resins, the degree of curing of blends are decreased, but pot life is prolonged, and tensile shear strength of steel bonds is increased.
2) It is observed that effects of the amount of xylene formaldehyde resins and curing condition on tensile shear strength vary with the kind of xylene formaldehyde resin, because of the difference in chemical structure of xylene formaldehyde resins and their reactivity to epoxy resin.
3) It is found that a limited region of compatibility, between 80 and 100 phr, exists for 100% xylene formaldehyde resin in epoxy resin. It is also found that joint strength is reduced with higher viscosity and molecular weight of 100% xylene formaldehyde resin in the case of 80 phr blends, and that these results have some relation to the dispersion state of xylene formaldehyde resin in epoxy resin, judging from the cured adhesive film observed under a phase contrast microscope. 相似文献
1) Generally, by the addition of xylene formaldehyde resins, the degree of curing of blends are decreased, but pot life is prolonged, and tensile shear strength of steel bonds is increased.
2) It is observed that effects of the amount of xylene formaldehyde resins and curing condition on tensile shear strength vary with the kind of xylene formaldehyde resin, because of the difference in chemical structure of xylene formaldehyde resins and their reactivity to epoxy resin.
3) It is found that a limited region of compatibility, between 80 and 100 phr, exists for 100% xylene formaldehyde resin in epoxy resin. It is also found that joint strength is reduced with higher viscosity and molecular weight of 100% xylene formaldehyde resin in the case of 80 phr blends, and that these results have some relation to the dispersion state of xylene formaldehyde resin in epoxy resin, judging from the cured adhesive film observed under a phase contrast microscope. 相似文献
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用两段淤浆聚合工艺合成了具有宽峰或双峰相对分子质量分布的高密度聚乙烯(HDPE)/(乙烯/丁烯-1)共聚树脂的反应釜共混聚合物。随着丁烯-1用量的增加,共混物的密度、熔点、结晶度、拉伸屈服应力减小,而断裂伸长率增加。随着高相对分子质量共聚物的含量增加,熔点、密度、结晶度减小,相对分子质量分布的双峰特性也更明显。通过调整两段聚合物的熔体流动速率、两段聚合物之比来控制相对分子质量大小及其分布。控制第一段小分子数目,增加第二段相对分子质量或减小密度可获得最大耐环境应力开裂性能。 相似文献
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Mark L. Crowder Amod A. Ogale Eugene R. Moore Brian D. Dalke 《Polymer Engineering and Science》1994,34(19):1497-1505
This study investigated the interrelationship between strength and flow characteristics of general-purpose polystyrene (GPPS) used in injection molding applications. The ease of flow was chosen as a measure of processability and was evaluated using the melt flow rate and capillary rheometer techniques. Of the different strength tests that were examined, flexural and notched tensile strength tests were most effective in differentiating between commercial grades of high and low molecular weight GPPS. While characterizing strength of injection molded specimens, the degree of molecular orientation was taken into consideration. For unplasticized resins, increasing the weight average molecular weight by about 100,000 enhanced the flexural strength by 10%, but also increased the viscosity at low shear rates (10 to 100 s?1). The increase in molecular weight had virtually no effect on viscosity at the highest shear rates (up to 10,000 s?1). Plasticized resins displayed a 6% loss in flexural strength as well as a significant reduction in viscosity (throughout the shear rate range) as compared with the unplasticized resins. As expected, the improvement in strength achieved by increasing molecular weight leads to a simultaneous increase in the viscosity, i.e., a deterioration of processability. In addition, our study indicates that for samples without preferential molecular orientation, narrowing the molecular weight distribution significantly improves the balance of strength and melt flow rate properties. 相似文献
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