水性聚氨酯纳米复合涂料的制备

通过接枝法制备了丙烯酸改性聚氨酯(PUA)乳液,重点研究引发剂用量对PUA黏度和转化率的影响。结果表明,0.3%用量的引发剂取得了较高的转化率,制得了稳定性好、性能优异的PUA乳液。以合成的PUA为基础,分别以纳米级的Al2O3、ITO和SiO2等为填料,配制成具有良好耐磨性、隔热性和UV屏蔽性等特殊功能的水性聚氨酯纳米复合涂料,并进行性能测试。     

氨基硅烷偶联剂改性水性聚氨酯木器涂料的研制

以甲苯二异氰酸酯、聚醚二醇、二羟甲基丙酸为原料,通过高分子反应得到预聚体,将此预聚体在低浓度的氨基硅烷偶联剂溶液中扩链,制得一种氨基硅烷偶联剂改性的聚氨酯水乳液。性能测试结果表明:以此乳液再配以其它助剂制得的水性聚氨酯木器涂料,具有优异的附着力、耐水性和力学性能。     

水性聚氨酯树脂的合成和性质研究

通过对不同体系、不同配方下水性聚氨酯乳液及其涂膜的研究,发现了不同种类的二异氰酸酯、二元醇,不同含量的亲水单体、亲水基团以及改性单体、扩链剂、溶剂等对水性聚氨酯性能均有影响,得到适用于木器漆、皮革织物类涂层、防水涂料等的水性聚氨酯树脂。     

聚丙烯酸酯共混改性水性聚氨酯乳液性能研究

自制水性聚氨酯乳液,并采用共混方法制备聚丙烯酸酯改性水性聚氨酯乳液。研究了共混改性涂膜的结构和性能,结果表明,聚丙烯酸酯共混改性水性聚氨酯乳液的涂膜性能比水性聚氨酯乳液涂膜性能有明显的提高。经过机械共混改性后,PU/PA膜的耐热性有了较大的提高,拉伸强度比PU膜大,而膜变硬、断裂伸长率大大降低。     

聚氨酯改性聚丙烯酸酯复合乳液的合成及其膜性能研究

通过原位乳液聚合法和物理共混法分别制备了水性聚氨酯改性丙烯酸酯复合乳液（PU／PA和PUA）,并对不同改性方法制得的乳液进行了对比研究。通过红外（FT-IR）、透射电镜（TEM）、差示扫描量热（DSC）、力学性能测试、原子力显微镜（AFM）等研究了聚氨酯改性丙烯酸酯乳液及涂膜的结构和性能。结果表明,改性后的复合乳液较PA在耐溶剂、拉伸等膜性能提高,耐水性能稍有下降;原位乳液聚合法PUA乳液综合性能优于物理共混PU／PA乳液。     

水性聚氨酯弹性树脂及其建筑防水涂料的制备与研究

研究水性聚氨酯(PU)弹性树脂、水性聚氨酯/丙烯酸酯(PU/PA)复合弹性树脂及其建筑防水涂料的合成与制备。考察不同聚醚、-NCO/-OH比值、亲水单体用量、扩链交联及PA/PU比值等因素对水性树脂力学性能,固含量和耐水性等的影响。探讨填料/乳液配比、增塑剂用量对防水涂料力学性能、同含量和低温柔性的影响。研究表明,所制得的水性聚氨酯弹性树脂及其防水涂料强度高、弹性好,属于新型的高性能环保型建筑材料。     

新型聚氨酯改性环氧水性涂料的研制

先用聚氨酯对环氧树脂进行改性,然后将改性后的环氧树脂与甘氨酸反应,成功制备了系列不同固含量的稳定的水性环氧乳液。性能测试结果表明,所制的水性环氧树脂在有机溶剂中的溶解性变差,在碱性水溶液中的溶解性增强;作为水性环氧涂料,由于结合了传统聚氨酯改性环氧树脂技术,其固化物具有优良的涂膜性能,特别是在柔韧性和耐磨性方面得到更明显的改善。     

聚氨酯——丙烯酸酯乳液的结构与性能

以蓖麻油与聚醚(N210,Mn=1000)、甲苯二异氰酸酯(TDI)为主要原料,乙二醇和二乙烯三胺进行两次扩链,引入环氧氯丙烷、马来酸酐等亲水单体,通过丙酮法制得了稳定的水性聚氨酯乳液。将乳液与外加乳化剂、水混合后加入含有偶氮二异丁腈(AIBN)的丙烯酸丁酯溶液,在80℃反应3h,再升温反应1h,可得到稳定的聚氨酯 丙烯酸酯乳液,使聚丙烯酸酯的耐溶剂性能有较大的提高,并对其进行了红外光谱、透射电镜以及DSC分析。结果表明,聚氨酯乳液和聚丙烯酸酯乳液并不是简单的机械共混,而是部分PU所含的CC双键和BA发生接枝共聚反应,构成了网络(I)PU富集在壳层,网络(Ⅱ)PA富集在核的近似核壳结构,并且二者分子链相互贯穿与缠结,形成了互穿网络结构。     

丙烯酸改性水性聚氨酯乳液的合成及表征

采用接枝法制备丙烯酸改性水性聚氨酯(PUA)乳液,研究了二羟甲基丙酸(DMPA)、甲基丙烯酸甲酯(MMA)对PUA乳液吸水率、黏度及涂膜硬度的影响,并用红外分析法表征了水性PUA与水性PU和共混型PU/PA在分子结构上的差异。     

丙烯酸酯改性聚氨酯水性分散体的结构形态特征

利用两种不同的聚合工艺制备得到组成相同的丙烯酸酯改性水性聚氨酯分散体。系列聚合物乳液的存在形态及成膜物结构与聚合工艺有关。丙烯酸改性与乳化同时进行时,其聚合物链结构中软、硬段分布均匀;而采用在溶剂相中改性接枝再乳化分散的方式,分子链中软硬段的微相分离加剧,热稳定性提高。而不同的聚合改性方式对涂膜的耐水性都有明显的改善,只是先聚合改性后乳化的工艺,乳液的贮存稳定性更好。     

有机蒙脱土改性水性聚氨酯的研究

以有机蒙脱土（OMMT）、聚氧化丙烯二醇、异佛尔酮二异氰酸脂、二羟甲基丙酸为基本原料,采用插层聚合的方法制备了水性聚氨酯乳液。对这种材料进行粒径、吸水率、机械拉伸、SEM、TEM、DMA等方面的测试,与材料改性前进行比较,分析了有机蒙脱土在水性聚氨酯中的分布情况,并讨论了有机蒙脱土的添加对水性聚氨酯材料性能的影响。     

内交联型水性聚氨酯的合成及其性能研究

采用IPDI型二异氰酸酯为主要原料,与聚醚2020反应,同时添加聚醚3050,合成了内交联型水性聚氨酯乳液,并对影响乳液稳定的因素及胶膜的力学性能进行了研究。     

苯乙烯-丙烯酸酯改性水性聚氨酯复合乳液的研制

以双丙酮丙烯酰胺为交联剂,苯乙烯和丙烯酸酯为改性剂,进行自由基引发聚合,制备了高性能的苯乙烯-丙烯酸酯改性水性聚氨酯复合乳液。采用红外光谱和示差扫描量热法对乳液进行了分析,讨论了改性剂、St和交联剂的用量对乳液和胶膜性能的影响。实验结果表明,当改性剂苯丙乳液的用量为28％,其中St用量为15％、交联剂用量为2％时,改性的复合乳液综合性能较佳。     

ATO/WPU复合隔热涂料的制备与性能研究

将异佛尔酮二异氰酸酯(IPDI)、聚醚220和二羟甲基丙酸(DMPA)等原料通过丙酮法合成水性聚氨酯(WPU),与纳米氧化锡锑(ATO)分散液复合后制得ATO/WPU复合隔热涂料.研究了DMPA用量和NCO/OH摩尔比对涂膜吸水率和硬度的影响,分析了ATO用量对涂膜隔热效果和透射光谱的影响.结果表明,DMPA用量5％,NCO/OH摩尔比为1.2,ATO的质量百分数为6％时,制得的涂膜硬度为2H,吸水率为15％,可见光区平均透过率达65％以上,红外区平均透过率仅33.51％,其隔热效果比空白玻璃可降温达9℃.     

Effect of aggregate type on properties of hardened self-consolidating lightweight concrete (SCLC)

In this study, the effects of aggregate type on the physical and mechanical properties of hardened self-consolidating concrete produced with lightweight aggregate (SCLC) were investigated. In experiments, three coarse lightweight aggregate (LWA) types, pumice, volcanic tuff and diatomite, and normal limestone aggregate were used. Different combinations of water to binder ratio and superplasticizer dosage levels were prepared for the SCLC mixtures. The total powder content (cement and mineral additives) was constant in the experiments. Physical properties such as thermal conductivity, dry unit weight, porosity and capillarity; mechanical properties such as compressive and splitting tensile strength, modulus of elasticity and abrasion resistance were determined in hardened condition. The results, in general, showed that SCLC with LWA in lower unit weight has lower mechanical and physical properties except for thermal properties when compared to properties of SCC.     

Modeling equilibrium adsorption of organic micropollutants onto activated carbon

Solute hydrophobicity, polarizability, aromaticity and the presence of H-bond donor/acceptor groups have been identified as important solute properties that affect the adsorption on activated carbon. However, the adsorption mechanisms related to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon loading on a specific activated carbon (F400) for solutes reflecting a wide range of solute properties. In order to improve prediction accuracy, groups (bins) of solutes with similar solute properties were defined and solute removals were predicted for each bin separately. With these individual linear models, coefficients of determination (R²) values ranging from 0.61 to 0.84 were obtained. With the mechanistic approach used in developing this predictive model, a strong relation with adsorption mechanisms is established, improving the interpretation and, ultimately, acceptance of the model.     

Utilizing rock mass properties for predicting TBM performance in hard rock condition

The key parameters on the estimation of tunnel-boring machine (TBM) performance are rock strength, toughness, discontinuity in rock mass, type of TBM and its specifications. The aim of this study is to both assess the influence of rock mass properties on TBM performance and construct a new empirical equation for estimation of the TBM performance. To achieve this aim, the database composed of actual measured TBM penetration rate and rock properties (i.e., uniaxial compressive strength, Brazilian tensile strength, rock brittleness/toughness, distance between planes of weakness, and orientation of discontinuities in rock mass) were established using the data collected from one hard rock TBM tunnel (the Queens Water Tunnel # 3, Stage 2) about 7.5 km long, New York City, USA. Intact rock properties were obtained from laboratory studies conducted at the Earth Mechanics Institute (EMI) in the Colorado School of Mines, CO, USA. Based on generated database, the statistical analyses were performed between available rock properties and measured TBM data in the field. The result revealed that rock mass properties have strong affect on TBM performance. It is concluded that TBM performance could be estimated as a function of rock properties utilizing new equation (r = 0.82).     

多孔混凝土的吸波特性

采用水平极化方式,在微波暗室中对试样进行了雷达散射截面(RCS)测试.结果表明:在8~18 GHz频率范围内,集料类型对电磁波反射率几乎无影响,多孔混凝土具有良好的吸波性能,其电磁波反射率小于-10 dB的波带宽度达到10 GHz,且平均反射率小于-20 dB;在一定范围内,增加孔隙率和集料粒径可改善多孔混凝土表面阻抗和自由阻抗的匹配性,降低电磁波的反射率.     

Low-temperature properties of styrene–butadiene–styrene polymer modified bitumens

Low-temperature properties of the modified bitumens containing styrene–butadiene–styrene (SBS) polymers were investigated using conventional methods, dynamic mechanical analysis (DMA) and bending beam rheometer (BBR). Effects of the characteristics of base bitumens and polymers and the proportion of the components on these properties were studied. The results indicated that SBS polymers improved low-temperature properties of bitumens. The degree of improvement generally increased with SBS content and were influenced slightly by SBS structure. The study also showed a statistically linear relationships between different low-temperature parameters.     

层布式钢纤维、混杂纤维混凝土的疲劳性能

层布式钢纤维、混杂纤维混凝土是一种新型的纤维增强混凝土材料,它是在经济与性能并重的基础上,选择钢纤维分层布置,或者在此基础上让有机纤维全体积乱向分布的纤维增强复合材料。通过对多年来层布式钢纤维、混杂纤维混凝土的疲劳特性进行了系统的总结,得到许多重要的规律和结论。作为一种公路路面材料,全面、深入地认识这种新型的复合材料的疲劳性能是其走向广泛应用的前提,结合多年的研究成果,介绍了这一新型材料的疲劳性能,并对已有的成果进行了简要的评价与展望。