巯基点击反应制备双重固化的水性混杂涂料

通过可逆加成-断裂链转移自由基(RAFT)乳液聚合的方法合成了一系列具有不同烯丙基/环氧基物质的量比的水性混杂乳液,将此混杂乳液与巯基封端的聚氨酯水分散体复合可制得含烯丙基/环氧基/巯基三种活性基团的水性混杂涂料,采用傅里叶红外光谱(FT-IR)对RAFT乳液和固化膜的结构及混杂涂料的固化过程进行研究,并研究了固化膜的性能。研究表明可通过RAFT乳液聚合制得具有预想结构的聚合物乳液,不同的固化条件对固化膜的性能有很大影响,在光/热双重固化的条件下,通过巯基点击反应制备的涂膜铅笔硬度为6H,耐甲乙酮的擦拭次数为1 000次,凝胶量为83.96%,耐冲击性>50 cm。     

新型水性丙烯酸/环氧杂化乳液的制备及其在水性双组分金属防护涂料中的应用

首先用丙烯酸酯单体和乳化剂预乳化环氧树脂,按照乳液聚合的工艺制备了水性丙烯酸/环氧杂化乳液;研究了杂化乳液合成过程中乳化剂种类和用量、功能单体的用量、乳液p H等参数对乳液性能的影响。在此基础上,使用该杂化乳液配制双组分水性环氧涂料,对涂层性能进行测试。结果表明:所制备水性丙烯酸/环氧杂化乳液具有较优的贮存稳定性,采用该杂化乳液配制双组分水性环氧涂料,涂膜具有优异的综合性能;与传统的双组分水性环氧涂料体系相比,该杂化涂料体系具有更长的适用期、更快的干燥速度,可广泛应用于包括防锈底漆和面漆在内的各种防腐涂料应用领域。     

SiO_2/PAE杂化乳液及建筑涂料的制备

采用共混法制备无机-有机杂化乳液及无机建筑涂料,研究有机聚合物乳液添加量对涂膜性能的影响规律。研究发现,添加适量有机聚合物乳液可以很好地改善硅溶胶的成膜性能;FT-IR测试发现硅溶胶与聚合物乳液发生了氢键缔合,杂化涂膜中的硅溶胶发生了凝胶化反应,生成Si—O—Si空间网络结构,但仍残留硅羟基;SEM图表明当聚合物乳液含量为60%时,无机相在涂膜的表面富集并以团聚体的形式镶嵌于聚合物涂膜中,而当聚合物含量为40%时,无机相已经全部穿插在有机相中,相界面几乎消失;通过配方优化得到综合性能优异的建筑涂料。     

水性聚氨酯/聚甲基丙烯酸甲酯杂化乳液的合成

用异佛尔酮二异氰酸酯(IPDI)、聚丙二醇(PPG)和二羟甲丙酸(DMPA)合成了水性聚氨酯分散体(WPU),讨论了PPG摩尔质量,NCO/OH及PPG/DMPA比例对WPU乳液和涂膜性能的影响。以WPU为种子与甲基丙烯酸甲酯进行乳液聚合制备杂化乳液,研究了不同PU/PMMA物质的量比例对杂化乳液及涂膜性能的影响,并采用TEM对WPU及杂化乳液粒子进行了表征。结果表明,在以PPG1000为原料,NCO与OH物质的量比为1.4∶1,PPG与DMPA物质的量比为1∶0.8条件下制备的WPU杂化乳液,随着PMMA比例增加,杂化乳液的稳定性和成膜性变差,聚合物膜断裂伸长率降低,但铅笔硬度、耐水性及耐乙醇性均得到了改善。     

巯基-烯/环氧光-热双重固化体系的制备与表征

通过光引发的巯基-烯点击化学反应和热引发的环氧开环反应制备了以烯丙基环氧树脂(DADGEBA)为基体树脂的巯基-烯/环氧杂化材料。通过实时红外(RT-FTIR)和傅里叶红外光谱(FT-IR)跟踪了双固化反应过程,以及不同官能度硫醇化合物对光聚合反应速率和转化率的影响。采用动态机械热分析(DMA)、热失重分析(TGA)和拉伸性能测试方法对烯丙基环氧树脂的光固化、热固化和光-热双固化3种固化材料的热力学性能和机械力学性能进行了对比研究。结果表明,烯丙基环氧树脂光-热双固化反应结合了光固化和热固化的优点,固化物的拉伸强度可以达到48 MPa,断裂伸长率为15%,玻璃化转变温度(T_g)为68℃,失重5%的热分解温度为343℃。     

有机无机杂化涂料

<正>201404009应用于铝材的采用短链全氟聚合物乳液的憎水性有机-无机杂化溶胶凝胶涂料的研制[刊,英]/Wankhede,Ruchi Grover等//Applied Surface Science.-2013(238).-1051~1059制备了一种应用于铝材上的有机-无机杂化的溶胶凝胶涂膜体系(厚度为5μm)。该涂膜中采用了环氧丙氧基三甲氧基硅烷(GPTMS)和甲基三甲氧基硅烷(MTMS)作为硅烷前体,与六甲基甲氧基三聚氰胺(HMMM)交联,随后用水性短链全氟乳液(FE)进行憎水性改性,提高了涂膜的憎水性,涂膜接触角约为     

无溶剂双组分BN/环氧/VMQ杂化聚硅氧烷涂料的研制

采用物理方法将烯丙基缩水甘油醚、纳米乙烯基甲基MQ硅树脂(VMQ)、硅烷偶联剂KH560和改性微米级导热氮化硼(BN)填料混杂分散在低黏度端乙烯基甲基硅油中,通过交联剂含氢甲基硅油、抑制剂乙炔基环己醇及Karstedt催化剂,制成室温流动性好、操作时间长的无溶剂型双组分BN/环氧/VMQ杂化聚硅氧烷涂料,并探讨了涂料的交联固化成膜机理。试验结果表明:通过VMQ改性的聚硅氧烷涂膜,拉伸强度和粘接强度显著提高,再经环氧改性后的粘接强度可进一步提高到1.2 MPa;随着BN掺量的增加,涂膜的导热率大幅提升。当乙烯基硅油质量为100份、VMQ为90份、烯丙基缩水甘油醚为2份和BN为60份时,热固化形成的杂化聚硅氧烷涂膜导热率可达到1.6 W/(m·K),失重10%时的温度可达631 K。     

绿色环境友好型水性环氧地坪涂料成膜性能影响因素探讨

采用水性环氧乳液、水性环氧固化剂、无重金属颜填料等环境友好型原材料作为水性环氧地坪涂料的成膜物质,制备了一种绿色环境友好型水性环氧地坪涂料,并对其成膜性能影响因素进行了简单探讨,结果表明:(1)环境温度(10℃)较低时,配方中可以加入4%成膜助剂,涂料的低温成膜性能最佳;(2)采用水性环氧乳液与水性环氧固化剂为主体,环氧基与胺氢当量配比为1∶1.2时,配方涂料的涂膜性能最佳;(3)实际施工过程中,保持良好的通风,相对湿度控制在20%～65%,温度在10～30℃范围内时,涂膜可以正常干燥固化。     

聚氨酯/含氟丙烯酸酯阳离子乳液制备及性能研究

以异佛尔酮二异氰酸酯、聚四氢呋喃醚二醇为原料,3-二甲胺基-1,2丙二醇为亲水扩链剂,丙烯酸羟乙酯为封端剂合成了部分双键封端的聚氨酯预聚体,并进一步制备了水性聚氨酯乳液。然后以丙烯酸六氟丁酯(F6BA)、甲基丙烯酸甲酯(MMA)为改性单体,采用种子乳液聚合法制备了阳离子型水性聚氨酯-含氟丙烯酸酯杂化乳液(WFPUA)。制备的乳液具有粒径小、粒度分布窄、乳液稳定性好等特点。考察了F6BA含量对涂膜疏水性能的影响,结果表明,MMA和F6BA用量分别为聚氨酯预聚体质量的25%和20%时,涂膜的水接触角为97.22°,吸水率为6.76%,具有良好的疏水性能。     

UV固化超支化PUA/SiO_2杂化涂料的制备及性能研究

以TEOS(正硅酸乙酯)为无机前驱体、KH-570(γ-甲基丙烯酰氧丙基三甲氧基硅烷)为改性剂,采用溶胶凝胶法在酸性催化条件下合成了改性硅溶胶;然后以HPUA[超支化PUA(聚氨酯丙烯酸酯)]为低聚物、PETA(季戊四醇三丙烯酸酯)为活性稀释剂,制备了UV(紫外光)固化HPUA/SiO_2杂化涂料。研究结果表明:杂化涂膜的热稳定性高于纯PUA涂膜;当w(改性硅溶胶)=16%(相对于单体总质量而言)时,杂化涂料的综合性能相对最好,其柔韧性为2 mm、铅笔硬度为4H和附着力为1级,并且涂膜的耐溶剂性、耐腐蚀性和耐磨性俱佳。     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.