羧基丁腈胶乳的研制

为制备石棉制品粘合用羧基丁腈胶乳,分别在500mL聚合瓶和30L聚合釜中,优选出了如下聚合配方和工艺条件:烷基苯磺酸盐用量2—5份(质量份),过硫酸盐用量1—2份,羧酸用量1—5份,丁二烯/丙烯腈为1.5—2.0;聚合温度30—50℃;聚合时间12—18 h;采用两次加料方式。按上述聚合配方和工艺条件分别在400L和8m~3聚合釜中进行了验证,所得胶乳性能为:总固物含量45％。pH值7.5—10,粘度80mPa·s,相对密度0.9900—0.1000,结合丙烯腈含量30％,结合羧酸含量2％—5％,平均粒径0.15—0.25μm。该胶乳与石棉制品的粘合性良好。     

胶乳汽提脱除单体的机理及数学模型

本文研究了丁苯吡胶乳的脱气机理,实验证明了这个包括有多个传质阶段的复杂传质过程是由单体从胶粒内扩散到表面并穿过界面进入液相的传质阶段所控制。从这一机理出发,选择了脱气过程的工艺条件。通过简化脱气过程的物理模型,从理论上推导出脱气过程的数学模型,并用实验证实了这一模型。通过对多种胶乳及各种脱气设备的应用,证明该模型具有普遍性。本文提出用定义的脱气速度常数来研究和设计脱气过程的方法。     

Semi-continuous emulsion copolymerization of butyl methacrylate with polymerizable anionic surfactants

Two polymerizable anionic surfactants sodium 4-(ω-acryloyloxyalkyl)oxy benzene sulfonate (SABS-n, n=8 or 10) have been successfully used in the semi-continuous emulsion copolymerization with butyl methacrylate (BMA). After generating seeding particles in an emulsion consisting SABS-8 or SABS-10 and small amount of BMA using a redox initiator ammonium persulfate (APS)/tetramethylethylenediamine (TMEDA) at room temperature, most of BMA was added drop-wise to the polymerizing emulsion system during a period of 4-8 h. These emulsion copolymerizations produced nanosized latexes with high polymer/surfactant weight ratios up to about 12/1 and nearly monodisperse particles ranging from 18 to 33 nm in diameter. X-ray photoelectron spectroscopy results showed that SABS-n was significantly enriched on the surface of latex particles. The effects of concentrations of SABS-n, BMA, and APS/TMEDA and the latex characteristics during the continuous addition of monomer were studied. A possible polymerization mechanism was proposed.     

专用丁苯胶乳对混凝土的改性

用自制的专用丁苯胶乳对混凝土进行改性,考察了聚合物与混凝土质量比(简称聚灰比)、水与混凝土质量比(简称水灰比)、消泡剂用量、养护条件和胶乳稳定性对改性混凝土性能的影响。结果表明,当聚灰比为12%、水灰比为35%、消泡剂质量分数为丁苯胶乳的3%时,且在混凝土浇铸后干养28d的条件下,改性混凝土的抗压强度、抗折强度、黏结强度及抗渗性比未改性混凝土分别提高了6%,9%,85%,50%。稳定性越好的胶乳对改性混凝土的性能提高幅度越大。     

超声波湿法混炼炭黑/天然橡胶复合材料的性能研究

利用超声波的乳化均质作用,将经水湿润的炭黑与稀释的天然胶乳混合均匀,然后采用蒸发成膜法和胶凝成膜法制备胶膜(炭黑/天然橡胶复合材料),探究制膜方法及超声波处理时间和功率对胶膜性能的影响。结果表明:蒸发成膜法成膜时间过长,打开的炭黑二次结构重新团聚,胶膜中炭黑分散性差,胶膜的拉伸强度较小,而胶凝成膜法稳定性更高,胶膜中炭黑分散性好;超声波处理时间为90 s、功率为840~960 W时,超声波的乳化均质效果最好,炭黑二次结构打开程度更高,此时采用胶凝成膜法制备胶膜,成膜速度快,炭黑来不及团聚,胶膜中炭黑分散性较好和结合橡胶较多,胶膜的拉伸强度较大。     

天然胶乳床垫和枕芯的发展

综述介绍天然胶乳床垫和枕芯的生产工艺、产品特性以及存在的问题。天然胶乳床垫和枕芯的生产工艺主要有邓禄普法和塔勒莱法胶乳发泡工艺,塔勒莱法工艺先进,但受设备结构复杂和投资大的限制,只有少数公司采用;邓禄普法性价比高,工艺趋于完善,被大多数厂家采用。天然胶乳床垫和枕芯具有优异的弹性、支撑性、透气性和抑菌抗螨功能,与睡眠者有良好的贴合性,可提高睡眠质量。巨大的市场需求导致天然胶乳床垫和枕芯产品存在部分假冒伪劣和粗制滥造产品,需要监管部门尽快制订产品标准并加强管理,引导和规范天然胶乳床垫和枕芯生产行业健康发展。     

丁苯橡胶/炭黑湿法预混胶的塑炼特性

基于胶乳/炭黑湿法混合的丁苯橡胶/炭黑湿法预混胶(P(SBR/CB))是一种在低剪切力环境下制备得到的炭黑在丁苯橡胶基体中分散优良的橡胶/炭黑预混胶,与采用传统机械混炼得到的充炭黑母胶相比,未经塑炼加工的P(SBR/CB)中的橡胶-炭黑相互作用较弱,故其加工行为表现出诸多新的特点。本文在分析P(SBR/CB)结构的基础上,采用实验室开炼机和Brabender转矩流变仪研究了其塑炼特性,探讨了开炼机薄通次数和密炼机塑炼工艺参数(循环油温、转速、塑炼时间等)对其塑炼特性(表观黏度、门尼黏度、排胶温度和结合胶含量)的影响规律,发现P(SBR/CB)的塑炼过程主要包括2个同时进行的进程,即炭黑网络的破坏和橡胶-炭黑相互作用的增强,且可通过调节密炼机塑炼参数,调控P(SBR/CB)混炼胶的门尼黏度和结合胶含量。     

耐盐雾改性苯丙乳液的合成

采用种子-半连续乳液聚合方法,以阴/非离子复合乳化剂为乳化体系,苯乙烯、丙烯酸丁酯等为共聚单体,丙烯酰胺（AM）为交联单体,环氧单体（GMA）为功能单体,硅烷偶联剂（KH-570）为偶联剂,制备了水性耐盐雾改性苯丙乳液,考察了AM、GMA、KH-570对乳液及其涂膜性能的影响.结果表明AM用量为1.0％,GMA、KH-570用量均为3.0％,涂膜交联度98.2％、吸水率7.8％、附着力1级、耐盐雾时间600h.     

新型阻燃氯丁胶乳阻燃、黏合体系及其浸渍工艺的研究

研究了新型阻燃氯丁胶乳的阻燃和黏合性能及其影响因素．试验结果表明,当Sb2O3的添加量为10．6份时,胶乳的阻燃性能大幅度提高;在CR中加入粘合剂RF／RA（添加量比为4：4．6）可在一定程度上提高帆布／橡胶层的黏合性能;浸渍工艺对阻燃和黏合也有一定程度的影响,且一浴浸渍异氰酸酯和环氧树脂,烘干温度为105℃,时间为10min,二浴采用15％的氯丁胶乳浸渍2次,并经过105℃预烘干和200℃快速定型,氯丁胶乳的阻燃和黏合强度最大．     

Electrical resistance and microstructure of latex modified carbon fiber reinforced cement composites

The electrical resistance,flexural strength,and microstructure of carbon fiber reinforced cement composites(CFRC) were improved greatly by adding water-redispersible latex powder.The electrical resistance of CFRC was investigated by two-probe method.The input range of CFRC based strain sensors was therefore increased,whereas electrical resistance was increased and remained in the perfect range of CFRC sensors.The analysis of scanning electron microscopy indicated that elastic latex bridges and a latex layer existed among the interspaces of the adjacent cement hydration products which were responsible for the enhancement of the flexural strength and electrical resistance.The formation mechanism of the elastic latex bridges was also discussed in detail.The continuous moving of two opposite interfaces of the latex solution-air along the interspaces of the adjacent hydrated crystals or colloids was attributed to the formation of the elastic latex bridges.