钛白粉种类对阻燃聚碳酸酯性能的影响

通过拉伸强度、缺口冲击强度、阻燃性能和色板外观等指标变化评价了4种牌号钛白粉对阻燃聚碳酸酯性能的影响,并探究了钛白粉种类对阻燃聚碳酸酯85℃/85%RH湿热老化性能和120℃热氧老化性能的影响。结果表明,添加钛白粉2233的聚碳酸酯老化后性能保持率最高,经过360 h湿热老化处理,ISO冲击强度保持率85.8%,ASTM冲击强度保持率99.1%;经过72 h热氧老化处理,ISO冲击强度保持率38.1%,ASTM冲击强度保持率57.7%。3款钛白粉改性阻燃PC的阻燃等级为UL94 V-0级(1.6 mm),添加钛白粉R248的阻燃PC的阻燃等级为UL94 V-1级(1.6 mm)。综上所述,四款钛白粉中2233的性能最佳。     

滑石粉对阻燃聚碳酸酯性能的影响

用滑石粉对钛白粉填充阻燃聚碳酸酯（PC）进行改性,研究了钛白粉以及滑石粉含量对阻燃PC的力学性能、阻燃性能、燃烧性能、热稳定性能以及抗老化性能的影响。结果表明,添加0.5 %~2 %（质量分数,下同）的滑石粉,阻燃PC的冲击强度下降了10 %,阻燃等级由UL 94 V?1级变为V-0级,总热释放量下降了4~8 MJ/m²,初始分解温度提高了8~10 ℃;同时,滑石粉能够提高阻燃PC的耐热氧老化以及湿热老化能力。     

PC/PBT合金体系热老化行为研究

利用动态扫描量热仪和傅立叶变换红外光谱仪研究了聚碳酸酯(PC)/聚对苯二甲酸丁二酯(PBT)合全体系的长期热老化性能.结果表明,3种酯交换抑制剂和两类抗氧剂时PC/PBT合金长期热老化性能有显著影响.PC/PBT合金长期热老化性能下降的原因是增韧剂的双键发生了化学变化,而酯交换作用和体系内PBT结晶结构的变化对合金黄变性能具有显著影响.     

硫化体系对氢化丁腈胶热氧老化性能的影响

系统研究了不同硫化体系对氢化丁腈胶（HNBR）力学性能和热氧老化性能的影响。结果表明：采用过氧化物/硫磺（S）体系得到的胶料其综合性能优于过氧化物体系得到的胶料,在100份HNBR中加入5份过氧化二异丙苯（DCP）和0.5份S,即DCP与S并用时,硫化胶拉伸强度可以达到23.85 MPa,在160℃×72 h热氧老化后仍可以达到20.99 MPa。热氧老化性能以DCP/S为7/0.5时最为优异。     

天然橡胶的热氧老化研究

为了改善天然橡胶的热氧老化性能，试验了防老剂D提纯品和工业品对天然橡胶热氧老化性能的影响，调试了其热氧化诱导期、热失重、热老化的性能变化。结果表明：含杂少纯度高的防老剂D使天然橡胶的抗热氧老化得到改善。     

抗水解剂及增韧剂对PBT耐湿热老化效果的影响

首先对特性黏度相近的不同牌号聚对苯二甲酸丁二酯(PBT)树脂在湿热老化试验后的强度和韧性保持率进行了比较;其次,考察了聚合型和单体型抗水解剂对PBT材料耐湿热老化性能的影响,并分析了聚合型抗水解剂用量与PBT耐湿热老化性能的关系;最后,对比了添加不同增韧剂的PBT材料经湿热老化试验后的力学性能保持率。结果表明,选用的5个牌号PBT树脂中,端羧基含量最低的树脂湿热老化900 h后拉伸和冲击强度保持率相对较好;添加聚合型抗水解剂较单体型可更为有效改善PBT材料的耐湿热老化性能,聚合型抗水解剂用量与材料力学性能保持率基本呈正向关系;含有甲基丙烯酸缩水甘油酯的增韧剂更有利于提升PBT材料耐湿热老化性能。     

橡胶防老剂S789的应用性能研究

研究S789在橡胶配方中的各种应用性能,重点是各种老化性能,并与6PPD、OPPD等同类防老剂进行比较。结果表明：S789防老剂整体性能略优于OPPD,但逊于6PPD。其中加工性能、硫化性能逊于6PPD、OPPD,物理性能优于OPPD,与6PPD相当。在抗热氧老化性能方面,S789优于6PPD和OPPD。在耐曲挠和抗臭氧性能方面,逊于6PPD,但优于OPPD. 同时,结果也表明,国产S789与国外同行在应用性能上互有优劣,总体相当。其中拉伸性能、结果性能、抗曲挠性能略优于国外同行,但抗热氧老化性能、抗臭氧老化性能略逊。     

热氧老化对聚碳酸酯结构和性能的影响

分别在90～120℃环境下,对聚碳酸酯(PC)进行人工热氧加速老化实验.研究PC老化后的结构性能变化和热氧老化机理.结果表明:在低于120℃温度条件下,老化120 h后,PC仍显示强而韧的性能,但断裂伸长减小;在120℃温度条件下,老化24 h后,PC拉伸断裂伸长消失;PC的热氧降解过程主要是以热诱导氧化降解反应,降解反应引起端基、侧基从主链断裂脱落,导致内部缺陷,力学性能随之下降.     

稀土防老剂对轮胎胎面胶的老化防护研究

研究稀土防老剂对轮胎胎面胶热氧和臭氧老化前后主要性能的影响,并与防老剂4010NA进行对比。结果表明:稀土防老剂对胶料热氧老化和臭氧老化的防护效果均优于防老剂4010NA;加入稀土防老剂Ⅰ的胶料具有较好的耐切割性能,热氧老化后撕裂强度保持率最大,对臭氧老化的防护效果最优;加入稀土防老剂Ⅱ的胶料经热氧老化后拉伸强度保持率最大,耐磨性能提高。     

芳纶的老化性能

介绍了芳纶的类型及国产杂环芳纶——STARAMID F-3的品种及规格,并以4种典型的芳纶——Kevlar49、STARAMID F-368、APMOC和PABI为代表,研究了结构对纤维结晶性能及力学性能的影响,重点研究了Kevlar49、STARAMID F-368、APMOC的热氧老化、湿热老化及日光老化性能,并详细探讨了影响老化性能的因素。     

Boiling water aging of polycarbonate and polycarbonate/acrylonitrile–butadiene–styrene resin and polycarbonate/low‐density polyester blends

The effects of boiling water on the mechanical and thermal properties and morphologies of polycarbonate (PC), PC/acrylonitrile–butadiene–styrene resin (PC/ABS), and PC/low‐density polyester (PC/LDPE) blends (compositions of PC/ABS and PC/LDPE blends were 80/20) were studied. PC and the PC/ABS blend had a transition from ductile to brittle materials after boiling water aging. The PC/LDPE blend was more resistant to boiling water aging than PC and the PC/ABS blend. The thermal properties of glass‐transition temperature (T_g) and melting temperature (T_m) in PC and the blends were measured by DSC. The T_g of PC and PC in the PC/ABS and PC/LDPE blends decreased after aging. The T_g of the ABS component in the PC/ABS blend did not change after aging. The supersaturated water in PC clustered around impurities or air bubbles leading to the formation of microcracks, which was the primary reason for the ductile–brittle transition in PC, and the microcracks could not recover after PC was treated at 160°C for 6 h. The PC/ABS blend showed slightly higher resistance to boiling water than did PC. The highest resistance to boiling water of the PC/LDPE blend may be attributed to its special structural morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 589–595, 2003     

聚丙烯/蒙脱土纳米复合材料的湿热老化性能

用熔融插层法制备了2种聚丙烯/蒙脱土(PP/OMMT)纳米复合材料,考察了在90℃的水中进行0~80 d不同时长的湿热老化后的产物特征。添加少量纳米化蒙脱土的PP表面形貌被破坏时间可延长20 d左右,比纯PP拉伸强度保持率提高67.5%,冲击强度保持率提高12.4%。PP、PP/OMMT复合材料湿热老化的损伤主要是环境中的水分子的直接物理作用,其中PP/季铵型OMMT纳米复合材料优良的抗湿热老化能力是其较高的结晶度、剥离性纳米化OMMT片层对水分子和热的物理阻隔效应以及OMMT与PP间较强的相互作用的共同结果。     

EVAC/ADP/MPP复合材料的抗老化性能

在乙烯–乙酸乙烯共聚物(EVAC)/二乙基次膦酸铝(ADP)/三聚氰胺聚磷酸盐(MPP)复合材料中加入紫外线吸收剂UV–531和抗氧剂1010,并对其进行老化性能研究,主要研究了"双85"湿热老化以及紫外老化对其力学性能以及热稳定性的影响。研究结果表明,经过"双85"湿热老化后,EVAC/ADP/MPP复合材料的拉伸强度和断裂伸长率都呈现出先上升后下降的趋势。经过紫外老化试验的EVAC/ADP/MPP复合材料的拉伸强度和断裂伸长率却都呈现出不断下降的趋势。通过红外光谱研究发现,EVAC/ADP/MPP在"双85"湿热老化试验时老化降解在乙烯和乙酸乙烯链段同时进行,而在紫外老化试验中老化降解主要发生在乙烯链段;热失重以及差示扫描量热分析发现,经过长时间的湿热以及紫外老化试验之后EVAC/ADP/MPP复合材料的热稳定性变差、残炭量变少。     

Influence of polyacrylate/titanium dioxide composite particles on the antiaging performance of polycarbonates

Polycarbonate (PC) and PC modified by polyacrylate/TiO₂ composite particles were exposed both in an outdoor environment with typical humid and hot climatic conditions in the Jiangjin area and in an indoor hygrothermal environment for accelerated aging. Then, the effects of the polyacrylate/TiO₂ composite particles on the antiaging performance of PC were investigated by measurement of the mechanical properties of PC before and after aging. The results show that the mechanical properties of PC decreased a lot after aging by the outdoor environment of the Jiangjin area. After accelerated aging by the indoor hygrothermal environment, the tensile strength and the bending strength of PC increased a little, and the elongation at break of PC decreased. The polyacrylate/TiO₂ composite particles effectively increased the elongation at break of PC aged by the hygrothermal environment and outdoor aging. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Recycled poly(ethylene terephthalate) and its short glass fibres composites: effects of hygrothermal aging on the thermo-mechanical behaviour

This paper reports on the effects of hygrothermal aging at 70 °C in water and at 80% relative humidity, on the thermo-mechanical properties, molar mass and microstructure of recycled poly(ethylene terephthalate) (rPET) and its short glass fibres composites.For all the investigated materials, the elastic mechanical properties (tensile and storage moduli) determined at low strain levels resulted practically unaffected by hygrothermal aging under the selected conditions. On the other hand, a marked reduction of the tensile strength and apparent fracture toughness has been observed for rPET matrix and its composites during hygrothermal aging, more markedly for materials immersed in water than for those aged at 80% RH. Both properties resulted to be related on the molar mass of the rPET matrix, that decreased during hygrothermal aging as a consequence of the hydrolysis process.The materials glass transition, evaluated as the temperature of the loss factor peak, increased during hygrothermal aging due to the progressively restricted mobility of the amorphous phase caused by a concurrent crystallinity increase. This crystallization process (chemicrystallization) is favoured by temperature, by the plasticizing effect of water and by the reduction of molar mass.Consistently with the mechanical measurements, the morphology of fracture surfaces exposed to hygrothermal aging in water revealed a reduction of plastic deformation of the rPET matrix and a weakening of the fibre-matrix interface for rPET composites.     

Lifetime Prediction and Aging Mechanism of Glass Fiber Reinforced Acrylate-Styrene-Acrylonitrile/Polycarbonate Composite under Hygrothermal Conditions

The development of fifth-generation technology has resulted in increased demand for materials with low dielectric losses and superior thermal and mechanical properties. However, ensuring the widespread use of such materials by investigating their aging mechanisms and operating lifetimes remains challenging. In this study, a glass-fiber (GF)-reinforced acrylate-styrene-acrylonitrile/polycarbonate (ASA/GF/PC) composite is designed and comprehensively investigated its aging behavior, mechanism, and service lifetime under long-term hygrothermal conditions. Based on the general Peck model, the composite maintains a high level of quality for over 10 years, including under harsh conditions of 40 °C and 80% relative humidity. The aging mechanism is primarily ascribed to cracking between the GF fibers and matrix, the breaking of chemical bonds, the generation of new cross-linked domains, and physical aging. These findings provide valuable insights into the long-term utilization of ASA/GF/PC composites in harsh environments.     

聚碳酸酯在沸水中的老化研究

研究了聚碳酸酯(PC)在沸水中的吸水规律和冷热水循环老化对PC结构和性能的影响.结果表明,PC在冷热水循环老化过程中发生了脆韧转变,在48 h内其冲击强度降低了90%.老化后,PC的玻璃化转变温度有所降低,并出现反常比热峰.冷热水循环老化后的PC试样出现了光散射现象,利用光学显微镜观察到该PC试样中存在圆盘状微孔,经热处理后发现该PC试样中出现的缺陷是不可恢复的.     

单向玻纤增强BMI复合材料的酸雨和温热老化行为

针对潮湿和酸雨多发地域的航空器用复合材料老化问题,模拟酸雨和温热(普通热水)环境,研究了单向玻璃纤维增强双马来酰亚胺树脂(BM I)复合材料(UGFRBC)吸水行为,通过红外光谱仪、力学测试装置、热力学分析装置分别表征了老化前后复合材料基体的结构、弯曲性能、层间剪切性能、动态粘弹性和玻璃化转变温度,分析了酸雨与温热环境下吸湿率对复合材料力学性能影响,建立了一种预测该复合材料酸雨和温热老化力学性能的经验公式。     

汽车用单组分环氧结构胶性能的研究

对一种汽车用单组分环氧结构胶的固化行为、固化工艺和力学性能进行了研究。结果表明：黏度随温度升高而降低,在固化工艺为175℃/30min时,力学性能达到最佳,在固化时间20min时,剪切强度达到最大值28.9MPa,并对其耐水、耐湿热和耐热等老化性能进行了研究,结果表明试样的性能变化不大,说明该环氧结构胶具有良好的耐老化性能。