天然胶乳与丁苯胶乳并用胶乳的性能研究

研究了停放时间、并用比对天然胶乳与丁苯胶乳并用胶乳胶体性能的影响,并测试了天然胶乳与丁苯胶乳共混胶乳胶膜的物理机械性能;用差示扫描量热仪(DSC)和热重分析(TG-DTG)法,分析表征并用胶乳的热性能.结果表明:随着停放时间的延长,并用胶乳的黏度显著下降,表面张力下降幅度不明显;随着天然胶乳在并用胶乳中比重的增加,表面张力随之增加;随天然胶乳用量的增加,并用胶乳胶膜力学性能逐步提高.     

月桂酸铵对浓缩天然胶乳贮存稳定性及硫化胶性能的影响

浓缩天然胶乳(简称浓缩胶乳)是制备天然胶乳制品的重要原材料,在其贮存过程中添加月桂酸铵作为稳定剂来提高胶乳稳定性.月桂酸铵对浓缩胶乳贮存稳定性及硫化胶性能有显著影响,进而影响其制品的性能.本研究通过对浓缩胶乳贮存过程中的机械稳定性(MST)和挥发脂肪酸(VAF)值变化情况进行分析,并对其硫化胶膜交联密度、力学性能和热稳定性能进行测试表征,研究月桂酸铵对浓缩胶乳贮存稳定性及硫化胶性能的影响.结果表明,加入月桂酸铵后,浓缩胶乳Zeta电位绝对值明显增加,乳胶粒子粒径变小,胶乳稳定性增强;月桂酸铵含量为0.050％～0.075％(质量分数,下同)时,浓缩胶乳的机械稳定性显著提高,MST值达到国家标准所需的最短贮存时间(20 d);月桂酸铵导致浓缩胶乳硫化速率降低,在相同预硫化时间下,加入月桂酸铵的浓缩胶乳硫化胶交联密度较低,硫化胶膜力学性能和热性能也下降.     

NL／AMP共混乳胶的研究

本文研究了天然胶乳与改性氨基树脂水分散体共混形成的橡胶共混胶乳的性能；共混胶乳中树脂组成与用量对共混胶乳的粘结性能及共混胶乳膜的物理机械性能、吸油率、吸湿率的影响。并通过扫描电镜观察了胶膜拉伸断面，橡胶沿条与帆布粘结剥离面的形态，了解树脂在橡胶中的分散状态和共混胶乳在橡胶沿条和帆布粘结层的渗透情况。结果表明：该共混胶乳的粘结性，胶膜的拉伸强度影响较大，对断裂伸长率，永久变形影响较小；树脂的用量影响     

BCT-2/NH3复合保存剂对浓缩天然胶乳保存效果及性能的影响

采用水溶性杀菌剂BCT-2与NH3复配作为浓缩天然胶乳的保存剂,研究了复合保存剂对浓缩天然胶乳保存效果,预硫化胶乳粘度、成膜特性,硫化胶膜的干燥特性及物理力学性能的影响。结果表明,在BCT-2用量为0.05%(质量分数)、NH3用量为0.35%(质量分数)时,BCT-2/NH3复合保存剂对浓缩天然胶乳有很好的保存效果,在保存180天后,挥发脂肪酸值(VFA NO.)、机械稳定度(MST)均符合GB/T 8289-2008标准的要求,尤其是VFA NO.仅为0.03,远低于国标0.08;预硫化胶乳停放5天后粘度变化不大,且成膜特性良好,胶膜干燥时间短,干燥速率常数为9.04×103 min-1;与用NH3+TT/ZnO作保存剂时相比,硫化胶膜的拉伸强度变化不大,但撕裂强度达到了53.72kN/m,提高了9.55kN/m。     

硅-丙共聚物微胶乳的合成及性能表征

通过连续乳液聚合方法合成了平均粒径59.8 nm、粒径分布窄、固含量达42%的硅-丙微胶乳。考察了聚合温度、乳化剂用量、引发剂用量、功能性单体用量对乳液及乳胶膜性能的影响。FT-IR分析表明,丙烯酸酯和有机硅发生共聚;反应温度为80℃~85℃时,得到的乳液的乳胶粒较小,而胶膜的吸水率随温度的升高而降低;乳化剂用量、引发剂用量、功能性单体M AA用量增加,胶膜吸水率增大;乳化剂用量为单体质量的4%、引发剂用量为单体质量的0.375%、M AA用量占单体质量的1%~2%时,乳液粒径最小;适量M AA的加入,可有效抑制反应过程中凝聚物的产生。     

膨胀型阻燃剂对硫化天然胶乳胶膜力学性能和阻燃性能的影响

以聚磷酸铵(APP)、季戊四醇(PER)和三聚氰铵(MEL)组成膨胀型阻燃体系(IFR),考察阻燃剂配比及用量对硫化天然胶乳力学性能和阻燃性能的影响,并通过热重分析仪分析其热稳定性、扫描电镜(SEM)分析阻燃剂在胶乳中的分散效果。结果表明,添加PER和MEL的硫化胶膜力学性能很好,但阻燃性能较差;添加APP和IFR的硫化胶膜力学性能较差,但是阻燃性能很好;SEM观察发现APP与橡胶相容性差;热失重分析可知,改性的硫化胶膜比未改性的硫化胶膜的阻燃性好,且IFR改性硫化胶膜的阻燃效果是最好。     

过氧化物预硫化天然胶乳硫化过程胶乳胶膜的热分析

用热重法-微商热重法(TG—DTG)和差热分祈(DTA)研究了用过氧化物预硫化胶乳过程中，硫化时间不同时胶乳胶膜热氧降解的过程。结果表明，过氧化物预硫化胶乳胶膜的起始降解温度、DTG峰顶温度和DTG峰的终止温度、起始放热温度和DTA峰顶温度均随硫化过程发生变化。     

P-(St-BA-UA-Na+)高分子电解质胶乳微球的理化性能研究

对由无皂乳液聚合法合成的苯乙烯－丙烯酸丁酯－十一烯酸的钠高分子电解质「Ｐ－（Ｓｔ－ＢＡ－ＵＡ－Ｎａ＾＋）」胶乳微球在离子介质中的物理化学进行了讨论。利用透射电子显微镜对不同介质条件下胶乳微球的形态,粒径及其分布进行了表征,认display status参与Ｓｔ,ＢＡ的共聚合链连于高分子链上可极大地提高乳化效率和乳液的稳定性,其用量对乳胶粒径影响在,介质ｐＨ对胶乳粒径分布有较大影响。     

过氧化物预硫化天然胶乳硫化反应的交联度及其医用胶乳制品热氧降解的研究

使用溶胀指数的测定方法研究叔丁基过氧化物预硫化天然胶乳(PPVL)胶膜硫化交联度,并采用热重分析法(TGA)研究空气状态下胶管试样热氧降解反应过程及其反应动力学.结果显示,过氧化物预硫化天然胶乳反应在70℃温度下硫化3.5h到达正硫点,此时胶膜溶胀指数为5.9.第一步热氧降解反应前,试样出现明显的吸氧增重现象,其最大热氧降解率Cp、最终热氧降解率Cf、反应活化能E和频率因子A均随β的增加而增大,表观活化能E0=107.5kJ/mol.     

改性天然胶乳/壳聚糖/明胶三元复合材料制备研究

采用正交试验方法,考察了原料的配比、交联剂的用量及交联温度等对复合材料性能的影响。较佳的制备工艺条件分别为改性天然胶乳/壳聚糖/明胶配比60/20/20,交联剂用量0.004%,交联温度60℃。随改性天然胶乳的加入,复合膜柔韧性增强,力学性能下降;壳聚糖对复合膜的力学性能贡献大于明胶。     

Conductive rubber composites from different blends of ethylene-propylene-diene rubber and nitrile rubber

Conductive rubber composites were derived from different blends of ethylene-propylene-diene monomer (EPDM) rubber and acrylonitrile butadiene rubber (NBR) containing acetylene black. The electrical and mechanical properties of these composites were measured. The percolation limit for achieving high conductivity of conductive filler depends on the viscosity of the blend. The higher the viscosity, the higher is the percolation limit. The conductivity rises with increasing temperature, and the activation energy of conduction increases with the decrease in the loading of conductive filler and percentage of NBR in the blend. Electrical hysteresis and an electrical resistivity difference during the heating-cooling cycle are observed for these systems, which is mainly due to some kind of irreversible change occurring in the conductive networks during heating. The mechanisms of conduction of these systems were discussed in the light of different theories. It was found that the degree of reinforcement by acetylene black in blends compares with those in the pure components NBR and EPDM. This is due to incompatibility of two elastomers in the blend. This revised version was published online in November 2006 with corrections to the Cover Date.     

硅橡胶/丁基橡胶共混体系的相容性研究

采用机械共混法制备了硅橡胶/丁基橡胶共混材料。通过理论分析、红外、动态力学性能、扫描电镜等初步考察了共混体系中硅橡胶和丁基橡胶的相容性。结果表明:硅橡胶/丁基橡胶共混体系属于热力学不相容体系,当丁基橡胶用量为50份时,硅橡胶呈连续相,丁基橡胶为分散相,随丁基橡胶用量的增加,硅橡胶和丁基橡胶呈部分双相连续的状态。     

金属橡胶/橡胶复合叠层耗能器动力学模型

针对橡胶常温低频段的阻尼性能差,设计开发了一种新型的金属橡胶／橡胶复合叠层耗能器。采用电液伺服材料试验机的位移加载方式,对该复合叠层耗能器进行了动态特性研究。在试验研究的基础上结合理论分析,建立了耗能器的动力学模型,并提出了一种迟滞回线分解识别算法,利用试验数据辨识出了模型中的未知参数。对比仿真与试验结果表明,所建模型可靠且参数识别精度能够满足工程应用的要求。     

Feasible incorporation of devulcanized rubber waste in virgin natural rubber

Devulcanized rubber waste produced from end-of-life passenger tyres by continuous shear flow stage control reaction technology was used both as filler and as part of rubber in a natural rubber matrix to develop the use of the rubber compound and lower the cost. The measurements of cure characteristics, swelling behaviour, crosslink density and dynamic and mechanical properties were carried out in our laboratory. In the present study it was found that using devulcanized rubber as part of rubber yields much better properties than using it as filler. Up to 15 phr devulcanized rubber used as filler and up to as much as 50 phr devulcanized rubber used as part of rubber can be incorporated in a new product without any noteworthy deterioration in performance arising.     

Investigations on the addition of styrene butadiene rubber in natural rubber and dichlorocarbene modified styrene butadiene rubber blends

This paper focuses on the use of styrene butadiene rubber (SBR) as a viscosity modifier in novel blends of natural rubber (NR) and dichlorocarbene modified styrene butadiene rubber (DCSBR). The processing characteristics, vulcanisation kinetics, stress-strain behaviour, mechanical properties and low temperature transition of the blends have been examined in order to analyse the influence of SBR in the blends. The change in cross-link density values from stress strain behaviour and equilibrium swelling data has been correlated with the technological properties of the blends. The excellent mechanical properties and the increased cross-link density in blends in the presence of 5—10 phr of styrene butadiene rubber reveals the viscosity modifying action of SBR in NR/DCSBR blends. The variation in viscosities of these blends with the addition of SBR is reflected in the DSC thermograms. The resulting blends show very high resistance to thermal ageing as compared to those without SBR.     

环保型水切割胶粉对天然橡胶力学性能和动态性能的影响

采用环保型水切割胶粉及力化学改性胶粉（MRP）与天然橡胶（NR）复合制备胶粉-NR复合胶,并探讨了胶粉用量对复合胶力学性能和动态性能的影响。通过红外和热失重分析确定了胶粉的主要成分为NR和丁苯橡胶（SBR）,且改性后胶粉大分子链结构未发生明显变化。通过橡胶加工分析仪研究了胶粉用量及改性对复合胶加工性能的影响。采用炭黑分散仪研究并观察了胶粉在NR中的分散情况。结果表明,胶粉改性后与NR的相容性提高,二者界面结合力增大,MRP-NR复合胶加工性能改善。炭黑分散结果表明,胶粉用量越多,其分散性越差,改性后胶粉的分散性提高,MRP-NR复合胶的力学性能最优,拉伸强度为27.9 MPa。     

橡胶相尺度对亚微米或纳米橡胶颗粒填充环氧复合材料性能的影响

对比研究了由液体橡胶在环氧树脂中原位形成的亚微米橡胶/环氧复合材料和在环氧树脂中直接添加纳米橡胶颗粒形成的纳米橡胶/环氧复合材料的性能。研究表明：未固化混合物的黏度随着纳米橡胶相的加入逐渐增加,但随着亚微米橡胶相含量的增加而降低;橡胶/环氧复合材料的玻璃化转变温度随着纳米橡胶颗粒的加入逐渐增加,但随着亚微米橡胶相含量的增加而降低;两种橡胶相的添加均使复合材料的弹性模量降低,断裂延伸率增加;在较低含量时,纳米橡胶颗粒可以提高环氧的拉伸强度;两种橡胶填充的橡胶/环氧复合材料均显示出明显的增韧效果。微观形貌分析表明,两种橡胶均可以在应力作用下脱粘并促进裂纹尖端的塑性变形。     

Buffing dust as a filler of carboxylated butadiene-acrylonitrile rubber and butadiene-acrylonitrile rubber

Buffing dust from chrome tanned leather is one of the difficult tannery wastes to manage. It is also hazardous to both human health and the environment. The scientific literature rarely reports studies on dust management, especially on its utilization as a filler for elastomers. In this connection we have made an attempt to use this leather waste as a filler for rubbers such as XNBR and NBR. The addition of the buffing dust to rubber mixes brought improvement in mechanical properties, and increase in resistance to thermal ageing as well as in electric conductivity and crosslink density of vulcalizates.     

Influence of carbon blacks on butadiene rubber/high styrene rubber/natural rubber with nanosilica: Morphology and wear

The effect of fillers on morphology and wear characteristics are studied in butadiene rubber (PBR)/high styrene rubber (HSR)/natural rubber (NR) blends with different types of carbon black. SAF N110 with SRF N774 type of carbon black shows a significant effect on curing studies and mechanical properties by reacting at the interface between PBR, HSR and NR matrix. Blends containing the same carbon blacks show high abrasion resistant properties against Du-Pont abrader, DIN abrader and different mining rock surfaces and also is found to be the toughest rubber against all types of rock.