尼龙12回收料的增韧及耐高温热氧老化改性研究

用熔融共混法制备了增韧尼龙12回收料复合材料,并采用热烘箱老化法研究了不同抗氧剂体系对尼龙12回收料及其增韧料高温热氧老化性能的影响。结果表明,增韧剂TA-11可在一定程度上提高尼龙12回收料的耐热氧老化性能,LS-3抗氧体系对增韧尼龙12回收料显示出极其优异的抗热氧老化效能。     

玻璃纤维增强PBT材料的热氧老化性能研究

以玻璃纤维增强聚对苯二甲酸丁二醇酯(PBT)材料为研究对象,探讨了受阻酚类抗氧剂、亚磷酸酯类抗氧剂、有机硫类抗氧剂与碳自由基捕捉剂等不同抗氧体系对PBT材料热稳定性、力学性能保持率与抗黄变性等热氧老化性能的影响。结果表明,采用添加碳自由基捕捉剂抗氧体系的PBT材料加工过程中热稳定性与耐黄变性能最好;采用亚磷酸酯类抗氧剂的PBT材料加工过程中耐黄变性能更好;采用有机硫类抗氧剂的PBT材料长期热氧老化过程中力学性能保持率与耐黄变性能最好;受阻酚抗氧剂、有机硫类抗氧剂与碳自由基捕捉剂复配的三元抗氧体系既可保证材料加工过程中热稳定性与耐黄变性能,又可改善材料长期热氧老化过程中力学性能保持率与耐黄变性能。     

热氧老化对长玻璃纤维增强聚酰胺6复合材料的影响

研究了160℃条件下不同热氧老化时间对未添加抗氧剂和添加抗氧剂的长玻璃纤维(LGF)增强聚酰胺(PA)6(PA 6/LGF)复合材料力学性能、热稳定性、结晶度及表面形貌的影响,并采用热重分析,差示扫描量热法分析和扫描电子显微镜观察对PA 6/LGF复合材料进行了表征。结果表明:PA 6基体分子链的断裂、降解以及LGF与PA 6基体的脱黏导致了PA 6/LGF复合材料宏观力学性能、熔融温度、结晶温度、结晶度以及热稳定性的下降。添加抗氧剂的PA 6/LGF复合材料拉伸强度保持率为83.9%,而未添加抗氧剂的复合材料则为76.8%。添加抗氧剂能使PA 6/LGF复合材料具有相对优异的力学性能保持率。     

汽车用增韧尼龙6的热氧老化研究

分别研究了马来酸酐接枝(乙烯/辛烯)共聚物(POE)、铜盐抗氧剂和受阻酚类抗氧剂1010、1098及其与亚磷酸酯类抗氧剂626复配体系对增韧改性尼龙(PA)6材料抗热氧老化性能的影响,研究了不同抗氧剂体系和热老化时间对材料拉伸强度、简支梁缺口冲击强度的影响。结果表明,在增韧PA6材料中添加合适的抗氧剂可以满足材料在160℃条件下热氧老化24 h后力学性能保持率在90%以上的要求,该材料可以应用于汽车燃油管路系统。     

聚丙烯抗热氧老化评价新方法研究

通过Haake转矩流变仪考察了不同抗氧剂及其添加量对聚丙烯(PP)热氧化分解的影响,筛选出抗氧效果优良的抗氧剂体系,并添加到滑石粉填充PP中,考察在150℃、113次/h换气速率条件下的热氧老化性能.研究发现,抗氧剂含量及接触面积对材料的热氧老化具有显著的影响,且转矩变化的时间与长期热氧老化有一定对应关系.这种测试转矩...     

抗老化助剂对尼龙6耐老化性能的影响

通过热氧老化评估了不同抗氧剂对尼龙6(PA6)耐黄变性能的影响,优选一组效果较好的抗氧剂作为基础抗氧剂配方。通过QUV 340 nm加速老化实验,分别评估了添加不同光稳定剂的PA6样品老化后其色差(△E)、黄色指数变化值(△YI)及拉伸强度保留率随时间的变化情况;通过长期热氧老化实验分别评估了样品在不同温度下,其△E、△YI及拉伸强度保留率随时间的变化情况。结果表明:Sunox508/Sunox626抗氧体系中加入光稳定剂会降低抗氧剂效果,其中加入Sunovin 5524/Sunovin 770影响最小。     

抗氧剂对SBS老化行为研究

研究了SBS添加不同抗氧体系的热氧老化行为,考察了SBS拉伸强度、扯断伸长率、扯断永久变形、硬度随热氧老化时间的变化规律,结果标明SBS在热氧老化过程中其拉伸强度、扯断伸长率会出现峰值,随后呈下降趋势,而SBS的扯断永久变形呈上升趋势,硬度则渐渐下降。选择抗氧体系对SBS抗热氧老化性能影响显著。     

抗氧剂1790对PP管材专用料的加工稳定性及高温热氧老化效能的评价

采用精炼加工、流变试验及长期热氧老化试验方法对抗氧化聚丙烯(PP)体系进行加工稳定性及抗热氧化效能评价,比较了抗氧剂1790及1010对PP动态热剪切老化和静态热氧老化性能的影响。结果表明,抗氧剂1790可以很好地改善PP树脂的加工性能和热稳定性能,添加抗氧剂1790的PP经150℃、2000 h热老化后,拉伸强度保持125%,伸长率保持80%。     

汽车用PA6/ABS带色合金材料的研究

选用聚酰胺(PA6)、丙烯腈-丁二烯-苯乙烯共聚物(ABS)高胶粉和相容剂,制备了PA6/ABS合金材料。研究了ABS用量对PA6/ABS合金材料加工性能和力学性能的影响。结果表明,ABS含量不同,挤出状态不同;ABS含量越高材料的流动性越差;随着ABS含量的降低,材料的拉伸强度依次升高,悬臂梁冲击强度和热变形温度呈不同的变化规律。选择PA6∶ABS=70∶25配方,对比不同抗氧剂时带色材料经热氧老化后颜色的变化及色粉含量增加后颜色的变化。结果表明,受阻酚类抗氧剂(1010)和硫醚类抗氧剂(DLTP)的复合抗氧体系和抗氧剂H10对抑制PA6/ABS合金材料热氧老化后的颜色黄变有很好的作用;通过添加钛白粉来增加色粉的含量可以明显降低材料经热氧老化后的颜色变化率,1010和DLTP的复合抗氧体系较抗氧剂H161能更好地抑制PA6/ABS合金材料热氧老化后C—N键的断裂和生色基团羰基的产生。研制的灰色PA6/ABS合金材料已应用于汽车儿童座椅配件。     

耐高温聚丙烯的热氧老化性能研究

通过粉化时间研究了耐高温聚丙烯的热氧老化性能,并考察了组分比、抗氧剂、黑色颜料对PP树脂粉化时间的影响。结果表明,不同耐高温PP的热氧老化性能存在差异,而组分比、抗氧剂、黑色母或色粉对材料的粉化时间都有显著影响。抗氧体系的存在能够大幅提高材料的粉化时间从而改善其热氧化性能,黑色颜料和抗氧剂共同作用时,抗氧剂在较低温度(160℃)对材料的热氧老化性能起主导作用,而颜料在较高温度(170℃)影响显著。     

Thermal aging performance of glass fiber/polyphenylene sulfide composites in high temperature

In order to use the glass fiber reinforced polyphenylene sulfide composites (GF/PPS) in high temperature environments, thermal aging performance of two kinds of commercial grade PPS composites, reinforced by 40% glass fiber, PPS-G40 HM and 1140L4, in thermal aging temperature of 250°C was compared by tensile strength, oxidized layer, color, crystallization and melting behavior. The results showed that tensile strength of GF/PPS composites is significantly decreased with increasing of aging time below 200 h and the tensile strength of aged PPS-G40 HM is higher than that of aged 1140L4. The thickness of dark color area is increased with increasing of aging time. The thickness of oxidized layer of 1140L4 is thinner than that of PPS-G40 HM. However, the color of oxidized layer of PPS-G40 HM is lighter than that of 1140L4. The recrystallization in thermal aging results in the formation of crystal with higher melting point and increased melting temperature of GF/PPS composites. It is found that addition of epoxy resin can increase the initial mechanical property and improve the thermal aging performance of GF/PPS composites. A novel modified GF/PPS composite with higher thermal aging properties was obtained.     

PA66/PP/晶须硅复合材料的制备与性能

通过双螺杆挤出机采用熔融共混的方法制备了尼龙(PA)66/聚丙烯(PP)/晶须硅复合材料.研究了偶联剂的种类以及晶须硅的用量对复合材料体系力学性能、微观形态和热性能的影响.结果表明,采用硅烷偶联剂KH560处理的晶须硅具有较好的分散性.晶须硅能够显著提高PA66/PP合金的拉伸和弯曲强度,对复合材料的韧性也有一定的改善...     

Improving the aging resistance of styrene‐butadiene‐styrene tri‐block copolymer and application in polymer‐modified asphalt

Thermal oxidation process of styrene‐butadiene‐styrene (SBS) copolymer was studied by using a variety of analytical and spectroscopic methods including thermal analysis, dynamic mechanical analysis and FTIR spectroscopy. The experimental results indicate that the thermal oxidation process of SBS is a free radical self‐catalyzed reaction containing four steps (initiation, growth, transfer, and termination of the chain) with both crosslinking and scission and the latter is confirmed to be the main process. The antioxidants 1010 as scavenger of free radicals and 168 acting decomposition of hydroperoxides were used to improve the oxidation aging resistance of SBS copolymer. It has been found that synergic effect of 1010 and 168 may be the best in practice and 0.2 wt % 1010 + 0.4 wt % 168 can effectively prevent SBS from the thermal oxidation at certain temperature. Furthermore, the aging resistance of the SBS‐modified asphalt was improved by addition of complex antioxidants. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of binary combined systems of antioxidants on the stabilization of peroxide‐cured low‐density polyethylene

The secondary antioxidants Irganox 168 and 242 and dilaurylthiodipropionate (didodecyl‐3,3′‐thiodipropionate) (DLTP) were chosen to be combined with the primary phenol antioxidants Irganox 300, 1010, 1035, and 1076, and the effects of the binary combined systems of antioxidants on the peroxide curing reaction and the long‐term stability of crosslinked low‐density polyethylene (XLPE) were studied through isothermal dynamic rheological and mechanical testing. The results show that the primary phenol antioxidants with lower melting points had better resistance to scorching and exhibited good synergistic effects with the secondary antioxidants. Irganox 168 had little resistance to scorching, whereas Irganox DLTP had moderate resistance, and Irganox 242 had the greatest resistance. Irganox 168 and DLTP guaranteed the mechanical properties well, whereas Irganox 242 reduced the tensile strength obviously. Irganox 300 and 1035 combined with secondary antioxidants performed poorly in long‐term thermal aging test, whereas Irganox 1076 in combination with secondary antioxidants displayed a moderate effect of aging resistance, and Irganox 1010 showed the best effect. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012     

改性碳纳米管增强热塑性聚氨酯复合材料的性能研究

以碳纳米管（CNTs）和热塑性聚氨酯（TPU）为原料,通过硫酸（H₂SO₄）/硝酸（HNO₃）混合溶液处理碳纳米管颗粒表面以达到改性的效果,使用改性过后的碳纳米管熔融共混制备出TPU/CNTs复合材料。研究了不同含量的CNTs对TPU基体的流变、力学、耐磨性以及热性能的影响。结果表明, 改性过后的CNTs在TPU基体中形成了良好的分散性和相容性;TPU/CNTs复合材料在高频剪切下保留了复合材料的加工流动性,并且复合材料的拉伸强度以及耐磨性相较于TPU有明显的增强,其中在改性碳纳米管含量较低时,复合材料的力学性能改善较为明显;改性CNTs的加入提高了TPU基体的熔融温度和结晶度;改性CNTs的加入提高了复合材料的热降解温度,提高了TPU基体的热稳定性。     

插层剂对PA66/蒙脱土纳米复合材料性能影响

将不同插层剂改性的蒙脱土与尼龙66(PA66)通过熔融共混制得了纳米复合材料,对复合材料的热变形温度和力学性能进行了研究。结果表明,与纯PA66相比,3种插层剂改性的蒙脱土／PA66纳米复合材料的热变形温度、弯曲模量、弯曲强度均有明显提高,拉伸模量和屈服强度也有所提高,但断裂伸长率和缺口冲击强度则明显下降;含极性羟基的插层剂对复合材料的综合改性效果较好,含2个长链非极性烃基的插层剂改性效果较差;加入环氧树脂后,复合材料的热变形温度、拉伸模量和弯曲模量有所降低,屈服强度、弯曲强度、断裂伸长率和缺口冲击强度则有所增加。     

Effects of heat accelerated aging on tensile strength of three dimensional braided/epoxy resin composites

The tensile tests of three‐dimensional (3Dim) and four‐directional (4Dir) carbon fiber braided/epoxy resin composites and carbon fiber woven plain fabric laminated/epoxy composites after heat accelerated aging at 150 and 180°C for 60, 120, and 180 h were carried out respectively. The reason of the changes of tensile property of these composites after different aging period of time at different high temperature was explained. The results of two‐way ANOVA analyzing indicate that the aging time has a significant effect on tensile strength of these composites. With the increase of accelerated aging period of time at high temperature, the tensile strengths of these composite samples decreased compared with that of composite samples without aging. However the decrease of tensile strength of 3Dim and 4Dir braided composites is less than that of laminated composites. One of the reasons is after aging for a long time at high temperature, the resin is damaged and becomes brittle which make the bonding force between fiber and resin decrease. Another reason is the structure of reinforcement of composites. After aging, the structure of 3Dim and 4Dir braided/epoxy resin composites still keeps the integrity which makes the 3Dim and 4Dir composites have less tensile performance degradation (3Dim and 4 Dir: three‐dimensional and four‐directional). POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Thermal Aging Properties of Graphite Fiber Reinforced Peek and Graphite Fiber Reinforced Bmi Composites

Graphite fiber reinforced poly(ether ether ketone) (PEEK) and graphite fiber reinforced bismaleimide (BMI) composite materials are two kinds of advanced fiber-reinforced polymer matrix composites with good thermal stability and excellent mechanical properties at high temperature. They are currently receiving considerable attention. the main limitation on their application is the lack of knowledge regarding their behaviors during extended use at high temperature. Thermal aging properties are the main parameters for new polymer matrix composites that will be used in advanced spacecraft structural components. From the results of thermal aging effects on the properties—including interlaminar shear strength, drop-weight impact strength, and impact energy—of graphite/PEEK and graphite/BMI composites, it is found that unidirectional graphite fiber reinforced composites retain higher strength compared to multidirectional, and that multidirectional graphite/PEEK composites keep higher property retentions than multidirectional graphite/BMI composites after thermal aging at 190°C. From scanning electron photomicrographs, it is also found that graphite/PEEK composites have better fiber/resin adhesion, intraply adhesion, and microcrack resistance compared to graphite/BMI composites after thermal aging.     

耐划伤剂对车用聚丙烯材料耐划伤和散发性能的影响

采用熔融共混挤出的方法,制备了聚丙烯/滑石粉/弹性体三元共混材料,并考察了两种耐划伤剂对材料耐划伤性能、散发性能和力学性能的影响。采用十字划伤仪和色差仪对材料在常温和热老化(102℃,168 h)条件下的耐划伤性能进行了评价;采用气味评定、顶空–气相色谱、挥发性有机化合物(VOC)袋子法以及雾度仪分别对添加两种耐划伤剂后材料的气味、总挥发性有机化合物(TVOC)以及VOC和雾度进行了测试。结果表明,采用酰胺类和有机硅类耐划伤剂可改善聚丙烯材料表面的耐划伤性能,常温下两者效果相当,但热老化后前者耐划伤性能消失,而后者仍具有良好的耐划伤性能。在散发性能方面,采用有机硅类耐划伤剂在气味等级、VOC、雾度等方面均优于酰胺类划伤剂。相对于酰胺类耐划伤剂,添加有机硅类耐划伤剂的材料韧性和熔体流动速率有所提升。通过使用有机硅类耐划伤剂制备了在耐划伤性能和散发性能上均满足材料要求的汽车零部件。