叔碳酸乙烯酯改性醋丙乳液的制备与性能研究

采用半连续种子乳液聚合,以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、乙酸乙烯酯(VAc)为主单体,丙烯酸(AA)为功能单体,叔碳酸乙烯酯(VeoVa10)为改性单体,合成了核壳型丙烯酸酯乳液。探讨了聚合温度、乳化剂、引发剂及功能单体与乳液性能的关系。通过单因素实验探讨了乳化剂用量、配比,改性单体用量等与乳液性能的关系。FT-IR和DSC测试结果表明,各单体之间发生了自由基共聚反应,乳液粒子为核壳结构。     

多单体熔融接枝聚丙烯的研究进展

介绍了聚丙烯(PP)多单体熔融接枝聚合技术,总结了现阶段对多单体熔融接枝PP的研究现状,分别阐述了多单体熔融接枝PP的影响因素、性能及结构,以及多单体熔融接枝PP在尼龙中的应用;并指出了其存在的问题及发展前景.     

超支化聚氨酯的合成与表征

以六亚甲基二异氰酸酯(HDI)为A2型单体,二乙醇胺(DEOA)为CBx型单体,采用A2+ CBx法,并结合逐步升温法和单体逐步加入法,制备高支化度和高代数的超支化聚氨酯.利用红外光谱仪(FT-IR)、核磁共振(NMR)、旋转流变仪(Rhe-ometer)等对目标产物进行结构和性能上的表征.研究结果表明:通过该方法可以制得超支化聚氨酯,支化度为76;与线性聚氨酯相比,该超支化聚氨酯具有更低的玻璃化转变温度和更优异的流变性能.     

梯度苯丙乳液的合成

以苯乙烯(St)和丙烯酸丁酯(BA)为主要核单体,甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为主要壳单体,甲基丙烯酸(MAA)和甲基丙烯酸羟丙酯(HPMA)为功能性单体,采用梯度乳液聚合法制备了硬核软壳型苯丙乳液。考察了聚合工艺,乳化剂的配比及含量,引发剂浓度,反应温度以及功能性单体含量对乳液聚合过程及性能的影响。结果表明:乳化剂占单体总量的1%,DSB/OP-10的质量比为2∶1,引发剂占单体总量的0.5%,反应温度为80℃,功能性单体含量为4%时,聚合稳定,凝胶量少,乳液性能优异,且采用梯度乳液聚合方式可有效降低乳液的最低成膜温度。通过红外光谱测定了苯丙共聚物的结构组成,透射电镜(TEM)对粒子结构进行分析,验证了其梯度结构形态。     

功能单体对丙烯酸酯乳液性能的影响

用功能单体衣康酸单丁酯(MBI)通过半连续法合成了水性涂料用丙烯酸酯乳液,探讨了功能单体MBI用量的变化对丙烯酸酯乳液性能的影响.结果表明:与功能单体AA制得的丙烯酸酯乳液相比,用功能单体MBI制备丙烯酸酯乳液时,乳液的聚合稳定性及化学稳定性好,粒子呈现规整的球形结构.当功能单体MBI的用量为4%时,制得的乳胶膜的耐水性最好,黏度最低.     

有色聚氨酯的合成及在超纤革中的应用研究

采用多种自显色的活性单体作为扩链剂,与二苯基甲烷二异氰酸酯(MDI)、聚四氢呋喃二醇(PTMG)合成了多种颜色的有色聚氨酯树脂,研究了显色单体结构及用量对有色聚氨酯耐溶剂性能及力学性能的影响,并以有色聚氨酯树脂与PA/co-PET定岛纤维无纺布通过碱减量制备了超细纤维革基布.结果表明,以显色单体碱性红2、分散蓝14、溶...     

联苯单元丙烯酸酯的合成及光固化研究

本文研究了含有液晶基元联苯的新型光活性单体的合成及结构表征。新型光活性单体与甲基丙烯酸β羟乙酯(HEMA)、光引发剂复配成光固化胶,研究了紫外光固化膜的硬度、冲击性能、柔韧性、耐溶剂性、耐水性及耐热性等性能与结构的关系。     

核壳结构的P(BA/LMA-St)制备及表征

以丙烯酸丁酯(BA)为核单体,甲基丙烯酸十二酯(LMA)或LMA和苯乙烯(St)为壳单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,采用分阶段饥饿态加料方式和半连续乳液聚合方法合成了具有核壳结构的P(BA/LMA)和P(BA/LMA-St)2个乳液体系.讨论了壳单体的滴加速度对2个体系乳液性能的影响,结果表明加入St...     

光敏聚酰亚胺的合成

光敏聚酰亚胺以其优良的性能在许多高新技术领域中得到了广泛的应用,是当今国内外学者的研究热点.采用均苯四酸二酐(PMDA)分别与4,4,-二氨基二苯醚(ODA)、3,3,-二甲基联苯胺(DMPA)进行三元共聚,通过改变两种二胺单体的摩尔比,合成出一系列光敏聚酰亚胺.采用IR、TGA等测试手段对聚合物的结构与性能进行了表征和研究.     

单体配比对PMI泡沫塑料结构和性能的影响

探讨了四种不同单体配比(甲基丙烯酸/甲基丙烯腈)对PMI泡沫塑料结构和性能的影响.结果发现随着单体配比的增加PMI泡沫塑料的泡孔孔径先增大后减小,在单体配比为50/50时泡孔孔径最小.同时发现PMI的密度与泡孔孔径成反比,孔径越小,密度越大.PM1泡沫塑料的力学性能与耐热性能与其密度成正比,密度越大,其力学性能和耐热性...     

Investigations of the properties of water films on quartz surfaces

Isotherms of water adsorption on and desorption from quartz surfaces have been determined. Thermal analysis curves of water thermodesorption from quartz surfaces have also been determined. From the experimental data, the energetic changes accompanying the water adsorption and desorption processes were calculated. The mechanism of water adsorption has been proposed, and conclusions concerning the structure and other properties of water films on quartz surfaces have been drawn.     

Polymer-water interaction and its relation to reverse osmosis desalination efficiency

Water and salt sorption and the homogeneity of water distribution have been determined in various polymers and compared with their reverse osmosis desalination properties. A general relationship between the polymer water sorption, the water distribution in the polymer matrix, and the membrane water- and salt-permeabilities has been determined, which indicates that the uniformity of water distribution in the polymer is an important parameter controlling reverse osmosis desalination efficiency.     

Phase equilibria in the calcium nitrate–water–isopropyl alcohol system

Results of an investigation of the solubility of the components of the water–isopropyl alcohol system in the temperature range of 253–268 K are given. Using fractional fusion, the concentrations of twocomponent water–isopropyl alcohol system have been determined, where fusion occurs more homogeneously. Phase diagrams of the calcium nitrate–water–isopropyl alcohol systems have been plotted at temperatures of 253, 263, and 268 K. The working area where compositions can be chosen for preparing the process liquid with a low freezing point has been determined.     

维生素B_6和维生素B_6酮的溶解度测定与关联

在室温接近 5 0℃的范围内 ,测定了维生素 B6 和维生素 B6 酮在水、乙醇、乙醇和水混合溶剂中的溶解度 ,实验数据用λh方程关联 ,绝对平均相对误差为 0 .95 % ,结果令人满意     

逆流式冷却塔性能分析及改造研究

根据实测数据及现场观察分析,找出了连铸冷却塔冷却能力不足的原因,在此基础上对淋水填料、布水系统、收水系统等进行了改造,并运用焓差法对冷却塔热力性能、通风阻力性能进行计算,确定了冷却塔核心部件淋水装置的改造参数.根据改造后的冷却塔性能检测的数据.证实冷却塔的热力性能得到了明显的提升.     

The effect of water on the solidification points of fatty acids. Solubility of water in fatty acids

Summary The effect of water on the solidification points of the normal saturated fatty acids from caproic to stearic, inclusive, has been investigated, and the depressions caused by given amounts of water in each of these acids has been presented. The solubility of water in six of the acids above their solidification points has been determined, and these data have been reported, together with rough approximations of the solubility of water in the other acids of this series.     

BTY型管式超滤器试验总结

本文介绍了ＢＴＹ型超滤装置用于印钞油墨废水处理的情况，实验证明，用该装置处理油墨水其透水量较高，对废水中的ＣＯＤ，悬浮物，含固量均具有很高的截留率，对ＮａＯＨ的回收率也较镐。实验确定了较佳的工艺操作条件，找出了波美度与含固量的定量关系，简化了废水分析，并对三种不同材质膜逐一进行性能考核，证明三种膜有适用于印钞油墨放心水的处理。     

Effect of carbon fibres on the mechanical properties and corrosion levels of reinforced portland cement mortars

The changes in mechanical properties of portland cement mortars due to the addition of carbon fibres (CF) to the mix have been studied. Compression and flexural strengths have been determined in relation to the amount of fibres added to the mix, water/binder ratio, curing time and porosity. Additionally, the corrosion level of reinforcing steel bars embedded in portland cement mortars containing CF and silica fume (SF) have also been investigated and reinforcing steel corrosion rates have been determined. As a consequence of the large concentration of oxygen groups in CF surface, a good interaction between the CF and the water of the mortar paste is to be expected. A CF content of 0.5% of cement weight implies an optimum increase in flexural strength and an increase in embedded steel corrosion.     

Synthesis and behaviour of two copolymers of poly[acrylamide-co-(N-(hydroxymethyl)acrylamide)] in ultrafiltration experiments

Summary Water absorbing materials on the basis of acrylamide copolymers have been investigated. The cross-linking of polymer chains strongly effects the degree of water absorption. The influence of starting composition of polyacrylamide : sodium hydroxide, duration of hydrolysis and irradiation conditions on cross-linking have been determined and optimized technological parameters have been derived. Water super absorbents with the ability to absorb up to 900g water by one gram material have been prepared. Received: 20 December 1999/Revised version: 19 June 2000/Accepted: 17 July 2000     

Calculation of some thermodynamic properties of gaseous water by means of BWR equation of state

A procedure for estimation of constants in the Benedict-Webb-Rubin (BWR) equation of state from experimental P-v-T data of methane, ammonia and water is proposed. The new BWR constants for water have been estimated in the range 366 to 1144 K and 0 to 38 MPa. Compressibility factor, enthalpy and entropy for water have been evaluated with average absolute percentage deviations of 0.127, 0.409 and 0.286 respectively. The BWR equation is compared with other simple as well as complex equations in which the constants have been determined in the usual way. In all cases the BWR equation was the most successful.