CaCO_3填料对聚丁烯-1热塑性弹性体防水卷材性能的影响

考察了CaCO3用量对聚丁烯-1热塑性弹性体防水卷材物理力学性能和热氧老化及碱老化后性能的影响。结果表明:随着CaCO3用量的增加,材料的拉伸强度、撕裂强度、定伸应力、断裂伸长率等均呈下降趋势;经过80℃×168h热氧老化后,随着CaCO3用量的增加材料的断裂伸长保持率逐渐下降,拉伸强度保持率逐渐增大,硬度上升;经过10%NaOH168h腐蚀后,随着CaCO3用量的增加,材料断裂伸长保持率先下降后上升,而材料的拉伸强度保持率先上升后基本保持不变;CaCO3的最佳用量为80phr。     

炭黑对聚丁烯-1热塑性弹性体防水卷材性能的影响

考察了炭黑用量对聚丁烯-1热塑性弹性体防水卷材力学性能以及热氧老化和碱老化后性能的影响。结果表明:随着炭黑用量的增加,材料的拉伸强度、断裂伸长率、定伸应力、硬度等均呈先上升后下降的趋势,当炭黑用量在25～30phr时,材料的强度达到最大值;经过80℃×168h热氧老化后,随着炭黑用量的增加,材料的断裂伸长率保持率呈下降趋势,而材料的拉伸强度保持率呈上升趋势;碱老化后,材料的硬度普遍上升;炭黑的最佳用量为25phr。     

芳烃油对聚丁烯-1热塑性弹性体防水卷材性能的影响

考察了芳烃油用量对聚丁烯-1热塑性弹性体防水卷材物理力学性能及热氧老化和耐碱性能的影响.结果表明随着芳烃油用量的增加,材料的拉伸强度、撕裂强度、定伸应力等下降,断裂伸长率上升;经过80℃×168 h热氧老化后,材料的断裂伸长率保持率和拉伸强度保持率均随着芳烃油用量的增加呈减小的趋势,硬度普遍上升;经过质量分数为10%的NaO)H 168 h腐蚀后,材料的断裂伸长率保持率和拉伸强度保持率随着芳烃油用量的增加呈下降趋势,硬度普遍上升;芳烃油的最佳用量为25份.     

外加剂及掺合料对瓷砖粘结砂浆性能影响研究

本文从减水剂、引气剂、早强剂、掺合料等方面分析对比了各因素对瓷砖粘结砂浆工作性能、拉伸粘结原强度、热老化后拉伸粘结强度的影响规律。结果表明,减水剂与引气剂均可显著改善粘结砂浆的施工性能与拉伸粘结强度;甲酸钙在标养条件下对瓷砖粘结砂浆的拉伸粘结强度的提升效果优于热养护制度;粉煤灰与滑石粉B(1000目)对粘结砂浆施工性能有较好的改善作用,但降低了其拉伸粘结强度。     

造纸“黑液”在PVC/NBR热塑性弹性体中的应用

以造纸黑液经硫酸中和处理脱水后的黑液干粉为填料,采用熔融共混法制备了聚氯乙烯(PVC)/丁腈橡胶(NBR)/黑液干粉热塑性弹性体复合材料。利用TGA测试了黑液干粉和热塑性弹性体复合材料的热降解性能。试验结果表明,黑液干粉中有机物与无机物的质量比为33/67,黑液干粉对弹性体的热降解无显著影响;热塑性弹性体复合材料力学性能测试结果表明,添加30份黑液干粉后,弹性体复合材料的100%定伸强度增加了7%,拉伸强度和伸长率分别下降了13%和37%;弹性体复合材料耐热氧老化(100℃、72h)性能试验结果表明,黑液干粉能改善弹性体的热氧老化性能,添加30份黑液干粉,老化后试样的拉伸强度增加了36%,拉断伸长率保留率为97%;而PVC/NBR弹性体老化后试样的拉伸强度增加了7%,拉断伸长率下降了15%。     

PP及PP/EPDM共混物室内外老化行为的研究

通过中国西部3个地区（新疆尉犁、西藏拉萨和四川成都）室外自然老化和室内加速老化（热氧、紫外老化）的对比,研究了聚丙烯及聚丙烯/三元乙丙橡胶（PP/EPDM）共混物室内外老化前后力学性能的变化和表面微观形态的变化,以及其室内外老化的对应关系。结果表明,室外老化初期PP的拉伸强度提高,老化中后期随着降解程度加剧拉伸强度下降;EPDM的加入提高了PP的耐老化性能,其中成都地区老化试样最为明显,24个月后拉伸强度保持率高达115 %;PP和PP/EPDM共混物室内热氧老化后拉伸强度变化不大,紫外老化后拉伸强度则呈现下降趋势;综合考虑热氧和紫外老化,通过时间等效关系可以更好地联系室内外老化,为预测材料在自然状态下的服役寿命奠定了基础。     

热预处理时间对EPDM/FKM性能影响及共混胶老化过程中交联密度变化的研究

研究了不同热预处理时间对EPDM/FKM性能的影响及共混胶老化过程中性能和交联密度变化。实验证明,随着预处理时间的延长,共混胶拉伸强度先上升后下降,扯断伸长率下降,硬度和100%定伸应力变大。热空气老化中,随着老化时间的延长,当热预处理时间为4 min时,拉伸强度先下降后上升;当预处理时间为6 min时,拉伸强度缓慢上升,扯断伸长率下降,硬度变大,100%定伸应力变大。老化过程中EPDM相交联密度增大,FKM相交联密度缓慢增大,共混胶总交联密度有所增加。综合考虑性能,热预处理时间为6 min较好。     

汽车内饰用聚丙烯材料老化性能分析

通过人工加速老化试验研究并分析了典型汽车内饰用聚丙烯(PP)材料老化后的力学性能、热性能与流动性能变化规律以及红外光谱(FTIR)。结果表明:随着老化时间的增加,PP材料的拉伸强度及弯曲强度均先提升后降低,分别在老化920和680 h时达到峰值;悬臂梁缺口冲击强度则逐步下降。材料老化后其熔体流动性能比老化前均有所下降,但下降程度与老化时间的关系不明显,其中老化480 h的材料流动性能下降幅度最小。当老化时间为720～1 400 h时,材料的流动性能随老化时间的增加而提升。FTIR分析结果显示,材料老化后聚合碳链氧化断裂,产生羧酸类降解产物。     

填料对聚硫密封胶性能的影响

通过加入中空微球降低聚硫密封胶的密度,讨论了中空微球及补强对密封胶热老化前后性能的影响。结果表明,加入中空微球后密封胶的密度下降,使用不同微球,密度和硬度差别不大,而仅75#微球有一定的补强作用,密封胶的耐热性急剧下降。补强填料提高了密封胶的密度,热老化前后的各项性能都比无填料体系高。使用A-380拉伸强度提高39%(老化后69%)、伸长率提高15%(老化后95%),同时其热老化前后性能变化率最低,拉伸强度、扯断伸长率、邵A硬度的变化率分别为3%、-84%、108%,优于无填料体系(-15%、-91%、118%);随着CaCO3含量的增加,密封胶的密度提高,热老化前后扯断伸长率均降低、邵A硬度均提高,而拉伸强度呈现先提高、后降低的规律,在含量为20份时最高,达到2.22MPa,比不加提高49%,老化前后的变化率为6%。研制的聚硫密封胶综合性能优异,热老化后质量损失小,仍呈现为弹性的橡胶状。     

双组分聚氨酯嵌缝粘结材料

江西宜春学院等单位以聚醚多元醇、TDI、煤焦油、蓖麻油、交联固化剂MOCA、催化剂及助剂为原料 ,经聚合、搅拌等工序 ,制出焦油型及阻燃型 2种双组分聚氨酯嵌缝粘结材料。该类材料NCO值约 3.8%～ 5 .0 % ,具有较佳的弹性与粘结强度(拉伸强度 ) ,可用于室内混凝土地板、天花板、预制板及地下土建工程、高速公路、体育场看台、停车场等的嵌缝施工 ,具有较好市场前景双组分聚氨酯嵌缝粘结材料@甲一     

JP-6新型导电胶的性能研究

对自制的JP-6新型导电胶性能进行了系统的研究,包括力学性能、电学性能以及耐热性和吸水性等。结果表明J:P-6新型导电胶是一种综合性能非常优异的导电胶黏剂体系,具有很高的拉伸剪切强度,高达21.1MPa;优良的导电性,其固化物的体积电阻率为2.32×10-4Ω·cm;良好的耐热性,其固化物的Tonset热分解温度高达375.6℃;很低的吸水性,只有0.5%;长的室温贮存期,高达3个月以上。而且具有优异的耐大气老化性能、耐热老化性能以及耐湿热老化性能等。     

Elastoplastic finite element stress analysis and strength evaluation of adhesive lap joints of hollow shafts subjected to tensile loads

The stress distributions in adhesive lap joints of dissimilar hollow shafts subjected to tensile loads have been analyzed by the elastoplastic finite element method, taking the nonlinear behaviors of the adhesive and the hollow shafts into consideration. A prediction method for the joint strength has been proposed based on the Mises equivalent stress distribution in the adhesive and the frictional resistance between the adhesive and the shaft after rupture of the adhesive. In the experiments, three different kinds of adhesive lap joints were made, i.e. the inner and outer hollow shafts were aluminum alloy/aluminum alloy, steel/steel, and steel/aluminum alloy combinations, and the tensile strength of each joint was measured. From the numerical calculations, in the case of the two hollow shafts made of the same material, the tensile strength increases with an increase of Young's modulus of the shaft and in the case of the two hollow shafts made of different materials, the tensile strength increases when the inner hollow shaft of larger Young's modulus is bonded to the outer one of smaller Young's modulus. Also, the effects of the overlap length and the inner diameter of the inner shaft on the tensile strength of the joint are discussed. By comparing the predicted values of the tensile strength with the experimental results, it was shown that the proposed prediction method could estimate the tensile strength of the adhesive lap joints of hollow shafts within an error of about 15%.     

PVC/锯末塑木材料的研制

以锯末和PVC胶粘剂为主要原料，用高速混合机制备了PVC／锯末塑木材料，并通过平板硫化机热压成型，制备出了新型的PVC／锯末塑木板材；测试了塑木板材的拉伸强度，弯曲强度，冲击强度，拉伸弹性模具，弯曲弹性模量等力学性能，讨论了增塑剂和胶粘剂用量对塑木板材性能的影响，实验结果表明：随增塑剂用量的增大，PVC／锯末塑木板材的刚性下降，韧性升高；随胶粘剂用量的增大，PVC／锯末塑木板材的力学性能和耐水性均有提高。     

聚乙烯醇/改性碱木质素发泡材料的制备与性能

以改性碱木质素与聚乙烯醇(PVA)为原料,甲醛为交联剂,采用无机发泡原理,制备了聚乙烯醇/碱木质素发泡材料(PLFM)、聚乙烯醇/环氧化碱木质素发泡材料(PELFM)和聚乙烯醇/羟甲基化碱木质素发泡材料(PHLFM),并利用红外光谱、扫描电镜、DSC及TG对发泡材料进行了测定及分析。结果表明, PVA用量为5 g时,环氧化碱木质素用量为50%(以PVA质量计,下同),甲醛用量24%,硫酸用量54%,固化温度120 ℃制备的PELFM拉伸强度最大,为17.26 MPa。FT-IR分析显示, PLFM和PHLFM的苯环5位均发生取代,而PELFM没有发生取代;SEM图片显示发泡材料的孔径不规则,孔隙率较大;与另两种发泡材料相比,PELFM拉伸性能低,表观密度较低,吸水倍率也较低。从DSC和TG分析可知,3种发泡材料中PELFM具有较低的玻璃态转变温度,但其生物相容性最好,PELFM失重率最高峰对应的峰值温度最大且介于碱木质素与PVA之间,烧失后残余量也最大,表明PELFM的耐热性更好,热稳定性更强。     

增粘剂对天然橡胶硫化特性及力学性能的影响

研究了增粘剂盐酸联胺和硫酸联胺对天然橡胶（NR）硫化特性及在热氧（热空气）、臭氧、光氧（紫外光）老化前后力学性能的影响。结果表明,随着盐酸联胺和硫酸联胺用量的增加,最大转矩（MH）和转矩差Δ（MH-ML）降低,焦烧时间（ts2）和正硫化时间（t90）延长,硫化速率（Vc）降低;热氧、臭氧、光氧老化前后定伸应力有所降低,热氧老化前的拉伸强度降低,老化后的拉伸强度增加,臭氧和光氧老化后的拉伸强度降低,拉断伸长率上升。     

Effects of salt spray on the mechanical properties of aluminum-epoxy adhesive joints

The aluminum bonding joints were aged in salt spray fog for various aging time from 0 to 1200?h. Uniaxial tensile tests were conducted for the joints to obtain the residual strength of the joints. The test results showed that the residual strength of the joints increases firstly and then decreases with the aging time in salt spray environment. The mechanism of the spray fog environment effect on the joint residual strength is analyzed by infrared spectral analysis and energy dispersive spectroscopy experiments. It is suggested the effect of aging time in the salt spray fog on the joint residual strength is the competing result of two mechanisms. One positive mechanism is that the adhesive expands after absorbing water in the early aging and reaches its saturation after a certain time, which leads to releasing of the internal stress in joints and consequently increases the joint residual strength. Another negative mechanism is that the water molecules permeating into the adhesive when aged in salt spray fog leads to the plasticization of the adhesive, which results in decreasing the joint residual strength as the aging time increases.     

等规聚丁烯-1管材料的耐热老化性能研究

等规聚丁烯-1(iPB-1)是一种优异的管道材料,特别适合制备薄壁小口径受压管材,iPB-1树脂近年已逐步国产化,但耐长期静液压定级实验评估长期使用寿命时仍有不足。经考察并对比Basell公司进口和国产两种iPB-1管材料在模拟长期静液压实验的95℃热水和空气气氛常压热烘条件下氧化诱导时间和拉伸性能的变化规律,发现国产iPB-1管材料短期耐水抽提性优于进口料但空气气氛下的耐热老化性略显偏弱,国产料改性后在95℃热水中4 000 h后的拉伸强度和断裂伸长优于进口料而杨氏模量偏低,有更突出的强度和韧性优势。     

A Method of Predicting the Stresses in Adhesive Joints after Cyclic Moisture Conditioning

The durability of adhesive joints is of special concern in structural applications and moisture has been identified as one of the major factors affecting joint durability. This is especially important in applications where joints are exposed to varying environmental conditions throughout their life. This paper presents a methodology to predict the stresses in adhesive joints under cyclic moisture conditioning. The single lap joints were manufactured from aluminium alloy 2024 T3 and the FM73®-BR127® adhesive-primer system. Experimental determination of the mechanical properties of the adhesive was carried out to measure the effect of moisture uptake on the strength of the adhesive. The experimental results revealed that the tensile strength of the adhesive decreased with increasing moisture content. The failure strength of the single lap joints also progressively degraded with time when conditioned at 50°C, immersed in water; however, most of the joint strength recovered after drying the joints. A novel finite element based methodology, which incorporated moisture history effects, was adopted to determine the stresses in the single lap joints after curing, conditioning, and tensile testing. A significant amount of thermal residual stress was present in the adhesive layer after curing the joints; however, hygroscopic expansion after the absorption of moisture provided some relief from the curing stresses. The finite element model used moisture history dependent mechanical properties to predict the stresses after application of tensile load on the joints. The maximum stresses were observed in the fillet areas in both the conditioned and the dried joints. Study of the stresses revealed that degradation in the strength of the adhesive was the major contributor in the strength loss of the adhesive joints and adhesive strength recovery also resulted in recovered joint strength. The presented methodology is generic in nature and may be used for various joint configurations as well as for other polymers and polymer matrix composites.     

碱木质素填充天然橡胶的特性研究

研究了碱木质素填充天然橡胶的规律,考察了胶料内填料网络结构特点及其对动态力学性能的影响。通过扫描电镜（SEM）、力学性能测试和动态力学性能测试对硫化胶进行观察和分析。结果表明：填充10%~50%碱木质素时,碱木质素在天然橡胶中几乎没有填料-填料相互作用,且橡胶-填料相互作用很弱,碱木质素颗粒之间发生了团聚;碱木质素填充后胶料的力学性能没有大的降低,填充10%碱木质素时,硫化胶的拉伸强度为30MPa,高于未填充碱木质素时的28.7MPa;碱木质素的加入一定程度地促进了橡胶的硫化,交联密度随着碱木质素的加入而增大,当碱木质素用量达到50%时交联密度有所下降,拉伸强度未20.1MPa;胶料的老化性能随碱木质素的加入得到改善;碱木质素的加入对硫化胶的抗湿滑性和滚动阻力没有明显影响。     

PBAT/PLA全生物降解薄膜的紫外光老化行为

采用挤出共混造粒、吹塑成型工艺制备了聚对苯二甲酸-己二酸丁二酯(PBAT)/聚乳酸(PLA)全生物降解薄膜。研究了薄膜在紫外光老化过程中热性能和横纵向力学性能随老化时间的变化,并利用红外光谱仪、X射线衍射仪、扫描电子显微镜对薄膜老化前后进行了表征。结果表明:在紫外光老化过程中,PBAT/PLA薄膜的横向拉伸强度和断裂拉伸应变均随着老化时间的延长不断减小,薄膜纵向拉伸强度和断裂标称应变随着老化时间的延长却先减小后增大,纵向的取向结晶结构有助于紫外光辐照交联的发生;紫外光老化更易发生在材料的无定型区,复合材料结晶度整体上不断增大。