聚酯聚醚混合型水性聚氨酯木器漆的合成及性能

以甲苯二异氰酸酯(TDI)为硬段,聚醚二元醇(N210),磺酸聚酯二元醇(BY3301),聚己二酸丁二醇酯二醇(PBA)为软段合成了一系列水性聚氨酯(WPU),通过调节大分子多元醇的比例,探讨WPU性能的变化。红外测试表征了水性聚氨酯的结构;吸水率、硬度、拉伸强度及热性能测试表明,随着N210含量的增加,聚氨酯胶膜硬度增加、吸水率降低,拉伸强度先增加后降低,最大可达41.61 MPa;随着BY3301含量的增加,胶膜的硬度、吸水率、以及拉伸强度均有增加。     

本期特约专栏主持人——许戈文

主持人语:水性聚氨酯胶粘剂是水性胶粘剂中的重要一类,具有聚氨酯材料"可裁剪性"的特点,继承了聚氨酯材料的全部优良性能,应用面也在迅速扩大。当今水性聚氨酯胶粘剂研究的重中之重是对其结构与性能关系的研究。本专题结合结构表征,重点讨论了聚氨酯结构中酯基含量和聚酯中侧基含量对胶膜力学性能的影响,以及磺酸型水性聚氨酯胶粘剂中催化剂的选择对胶膜力学性能的影响。为水性聚氨酯胶粘剂软段和亲水链段的研     

含侧基聚酯型聚氨酯耐水解性的研究

通过对比4种含有不同侧基结构的聚氨酯胶膜的力学性能和耐水解性,发现以含有较大空间位阻侧基的2-乙基-1,3-己二醇与己二酸合成聚酯二元醇（PEPO。EHO）为原料制备的聚氨酯胶膜具有较优异的耐水解性,而以1,3-丙二醇与己二酸合成聚酯二元醇（PEPO—PPD）为原料制备的聚氨酯胶膜具有较好的力学性能。选取PEPO-EHO与PEPO-PPD混合后制备出的聚氨酯胶膜力学性能和耐水解性较好。当PEPO-EHO与PEPO-PPD在软段中混合的质量分数分别为50％时,所制备的聚氨酯胶膜具有较好的综合性能。     

PPS基磺酸型水性聚氨酯的合成及其性能

探讨了氨基磺酸钠(PPS)基水性聚氨酯对催化剂的选择性,并合成了一系列稳定的高固含磺酸型水性聚氨酯(WPU)。乳液稳定性测试表明,1,8-二氮杂二环-7-十一烯(DBU)对聚氨酯的合成具有较好的催化作用,得到的乳液稳定性较好,DBU含量在0.15%时,胶膜的力学强度最优;FT-IR表征了磺酸型水性聚氨酯的结构;力学性能、DSC、TG测试表明,随着PPS含量的增加,胶膜的拉伸强度呈先增加后减小的趋势,当PPS含量在4.7%时,力学性能最优,达到42.13 MPa,断裂伸长率为404.57%,耐热性最优。     

聚醚硅氧烷二元醇改性蓖麻油基水性聚氨酯的合成及性能

以蓖麻油和聚醚硅氧烷二元醇(PEPSO)作为多元醇原料制备植物油基水性聚氨酯。在预聚体合成过程中,加入不同含量的聚醚硅氧烷二元醇,通过醇羟基与异氰酸酯基的反应,将PEPSO引入到植物油水性聚氨酯基体中,制备出PEPSO改性聚氨酯材料,并通过全反射傅里叶红外光谱仪测试、粒径测试、热稳定性测定、表面疏水性测试及力学性能测试探讨PEPSO的含量对聚氨酯乳液与胶膜材料的影响。结果表明,PEPSO成功接入到了聚氨酯分子主链中;随着PEPSO含量的增加,热稳定性逐渐提高,玻璃化转变温度(Tg)呈减小的趋势;少量PEPSO的加入可在一定程度上提高材料的疏水性及拉伸强度。     

UV固化改性蓖麻油基水性聚氨酯的制备及抗菌性能

以蓖麻油(CO)、异佛尔酮二异氰酸酯(IPDI)、阳离子扩链剂N-甲基二乙醇胺(MDEA)、封端剂甲基丙烯酸羟乙酯(HEMA)为主要原料,制备一系列紫外(UV)固化型蓖麻油基水性聚氨酯(UWPU)乳液.为进一步提升其抗菌性能,通过引入胍基的方法,制备出抗菌型UV固化蓖麻油基水性聚氨酯(GWPU)乳液.通过耐水性、抑菌圈、抗菌性能测试对制得胶膜性能进行了检测.结果表明,GWPU胶膜相对UWPU吸水率有所上升,但均保持在10％以下;GWPU胶膜抗菌方式为接触性杀菌,同时不具有浸出性;当氨基胍盐含量为UWPU胶膜质量的1.2％时,GWPU对金黄色葡萄球菌(S.aureus)、大肠杆菌(E.coli)的抗菌率均可达99.9％,且经过10 d抗菌测试后仍能保持99.9％的抗菌性.     

UV固化改性蓖麻油基水性聚氨酯的制备及抗菌性能

以蓖麻油(CO)、异佛尔酮二异氰酸酯(IPDI)、阳离子扩链剂N-甲基二乙醇胺(MDEA)、封端剂甲基丙烯酸羟乙酯(HEMA)为主要原料,制备一系列紫外(UV)固化型蓖麻油基水性聚氨酯(UWPU)乳液.为进一步提升其抗菌性能,通过引入胍基的方法,制备出抗菌型UV固化蓖麻油基水性聚氨酯(GWPU)乳液.通过耐水性、抑菌圈、抗菌性能测试对制得胶膜性能进行了检测.结果表明,GWPU胶膜相对UWPU吸水率有所上升,但均保持在10％以下;GWPU胶膜抗菌方式为接触性杀菌,同时不具有浸出性;当氨基胍盐含量为UWPU胶膜质量的1.2％时,GWPU对金黄色葡萄球菌(S.aureus)、大肠杆菌(E.coli)的抗菌率均可达99.9％,且经过10 d抗菌测试后仍能保持99.9％的抗菌性.     

三嗪基含氟扩链剂改性水性聚氨酯的合成

利用三聚氰氯（CC）、八氟戊醇（OFP）和乙醇胺（MEA）间的反应先合成了三嗪基含氟扩链剂CC-F，在此基础上制备出系列三嗪基含氟扩链剂改性水性聚氨酯CC-FPUF。利用FTIR和1HNMR对其结构进行表征，并用DLS、XRD、XPS、SEM、WCA和电子万能试验机探究了CC-FPUF制备中所用CC-F的含量(以CC-F、IPDI、CMA-1044、DMPA、S104、TMP和TEA的总质量为基准，下同）对CC-FPUF的乳液粒径、聚合物形态、胶膜形貌、表面元素组成、疏水性能和力学性能的影响。结果表明，随着CC-F含量的增加，CC-FPUF的乳液粒径、胶膜疏水性能和胶膜拉伸强度均有所增加。当CC-F的含量达到8%（CC-FPUF-8）时，胶膜的水接触角最高达到125.8°，相比不含氟的水性聚氨酯（PU）和CC-FPUF-0（CC-F的含量为0）分别增加了60.9°和34.1°；此时胶膜的拉伸强度最大，相比CC-FPUF-0增加了24.47 MPa。胶膜CC-FPUF-8表现出优异的疏水性能和良好的力学性能。     

UV固化改性蓖麻油基水性聚氨酯的制备及抗菌性能

以蓖麻油(CO)、异佛尔酮二异氰酸酯(IPDI)、阳离子扩链剂N-甲基二乙醇胺(MDEA)、封端剂甲基丙烯酸羟乙酯(HEMA)为主要原料,制备一系列紫外(UV)固化型蓖麻油基水性聚氨酯(UWPU)乳液.为进一步提升其抗菌性能,通过引入胍基的方法,制备出抗菌型UV固化蓖麻油基水性聚氨酯(GWPU)乳液.通过耐水性、抑菌圈、抗菌性能测试对制得胶膜性能进行了检测.结果表明,GWPU胶膜相对UWPU吸水率有所上升,但均保持在10％以下;GWPU胶膜抗菌方式为接触性杀菌,同时不具有浸出性;当氨基胍盐含量为UWPU胶膜质量的1.2％时,GWPU对金黄色葡萄球菌(S.aureus)、大肠杆菌(E.coli)的抗菌率均可达99.9％,且经过10 d抗菌测试后仍能保持99.9％的抗菌性.     

脲基含量和抗氧剂对HMDI型WPU耐黄变性的影响

以4,4'-二环己基甲烷二异氰酸酯(HMDI)、聚四氢呋喃二醇(PTMEG)或聚己二酸新戊二醇-1,4-丁二醇酯二醇(CMA654)为主要原料合成了水性聚氨酯(WPU)乳液,并制膜进行耐黄变性测试。探讨了聚氨酯分子链中脲基含量、抗氧剂的种类及添加量对WPU胶膜耐黄变性的影响。结果表明,提高脲基含量可以提高胶膜的耐黄变性;添加质量分数0.9%的2,6-二叔丁基对甲苯酚(BHT)或0.3%的抗氧剂1010可有效提高胶膜的耐黄变性;受阻酚与亚磷酸酯复配型抗氧剂相对于传统抗氧剂1010对胶膜的耐黄变性提高更为明显,且添加量少于单独使用抗氧剂1010。     

Novel luminescent polymers containing backbone triphenylamine groups and pendant quinoxaline groups

Novel, conjugated polyfluorene derivatives that comprised an electron-donating triphenylamine group in the backbone and pendant, electron-accepting quinoxaline moieties, were synthesized via the Suzuki coupling reaction and their UV–vis absorption, fluorescence emission and electrochemical properties were investigated. The copolymers were readily soluble in common organic solvents and displayed good film-forming ability and excellent thermal stability. Electroluminescence devices, comprising indium tin oxide/poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonic acid)/emitting polymer/Ba/Al, in which the polymers were employed as emissive layers, exhibited superior performance compared to that of corresponding, poly(9,9-dioctylfluorene) and poly(9,9-dioctylfluorene-co-4,4′-triphenylamine) based devices, indicating that the polymers offer promise as emissive materials in polymeric light-emitting diodes.     

Detection of similar successive groups in a model with diverging number of variable groups

Abstract

In this article, a linear model with grouped explanatory variables is considered. The idea is to perform an automatic detection of different successive groups of the unknown coefficients under the assumption that the number of groups is of the same order as the sample size. The standard least squares loss function and the quantile loss function are both used together with the fused and adaptive fused penalty to simultaneously estimate and group the unknown parameters. The proper convergence rate is given for the obtained estimators and the upper bound for the number of different successive group is derived. A simulation study is used to compare the empirical performance of the proposed fused and adaptive fused estimators, and a real application on the air quality data demonstrates the practical applicability of the proposed methods.     

Characterization of acidic groups in oxycelluloses. I. Identification of various functional groups

A large number of oxycelluloses were prepared and modified further by treatment with sodium borohydride as well as chlorous acid, and qualitative color tests were carried out to detect the presence of various functional groups. Uronic acid groups were found to be present in most of the samples. Enediol groups were not detected in any of the samples, although the samples after sodium carbonate treatment gave distinct color tests for enediols, indicating the presence of α-hydroxymonoketo groups. Characteristic color tests for lactones were observed for most of the samples. The intensity of color developed in the lactone test was, however, found to decrease progressively on contact with a KI–KIO₃ mixture for various periods. The difference in the values of carboxyl content between the methylene blue method and the iodometric method is thus mainly caused by the opening of lactones in the latter method.     

Polymers containing formamidine groups

Summary Aromatic polyformamidines were synthesized by high temperature solution polycondensation of aromatic diamines with triethyl orthoformate. In order to obtain high molecular weight polymers, general investigations on the influence of reaction conditions such as reaction time, temperature and solvent were carried out on the basis of polyformamidine prepared from 4,4'-methylenedianiline. The proposed structures of aromatic polyformamidines were confirmed by elemental analysis, NMR-and IR-spectroscopy. Molecular weights were determined by ¹H NMR end group analysis. Polyformamidines having inherent viscosities of 0.25–0.36 dl/g show excellent solubility in polar solvents and in strong acids. Thermal analysis indicated that these polymers are stable up to 300°C, and a 10% weight loss were recorded on the TG curves in the temperature range of 350–366°C in nitrogen.     

Polyphenylquinoxalines containing alkylenedioxy groups

A series of new polyphenylquinoxalines (PPQ) containing alkylenedioxy units within the backbone were prepared in high molecular weight forms (η_inh = 0.82–1.5 dL/g). The glass transition temperatures ranged between 203 and 241°C, decreasing with increasing length of the alkylenedioxy groups. Solution-cast films gave tensile strength, tensile modulus, and elongation at room temperature as high as 14,400 psi, 378,000 psi, and 8.1%, respectively. The PPQ were readily compression molded to provide compact tension specimens that gave fracture energy (G_Ic) as high as 10.5 in. lb/in.² Titanium to titanium tensile shear specimens provided average strengths of 4400 psi at 26°C, 3100 psi at 177°C, and 2010 psi at 203°C. The PPQ were resistant to normal aircraft fluids but were soluble in chlorinated solvents.     

Aryl-alkyl groups in coals

A method has been developed for detecting ethyl, propyl, and isopropyl substituents on aryl rings in coals. This method complements an earlier method for determining aryl-methyl groups. Examination of five coals showed that 0.1-0.3% of the carbon was in aryl-ethyl groups. Aryl-propyl, aryl-isopropyl, and larger aryl-alkyl groups were not detected. Aryl-methyl is the dominant aryl-alkyl group in coals and generally accounts for ≈1% of the carbon.     

Polymers containing formamidine groups

Summary Aliphatic polyformamidines have been synthesized by reaction of aliphatic diamines with triethyl orthoformate in presence of catalytic amounts of acetic acid. The reaction has been carried out in DMSO at 180°C. The polymer structure has been confirmed by IR and NMR spectroscopy. For determination of molecular weights ¹H NMR end group signals have been used.     

Polymers containing formamidine groups

Summary New aromatic polymers containing formamidine groups were prepared by high temperature solution polycondensation of triethyl orthoformate with various aromatic diamines. The resulting polyformamidines were characterized by elemental analysis, IR' and ¹H NMR spectroscopy, viscosity measurements, thermogravimetry, DSC- and WAXS measurements. With few exceptions aromatic polyformamidines show excellent solubility in polar solvents and strong acids, but they were gradually decomposed in extended contact with moisture. Polyformamidines containing rigid para structures are well crystallizing materials, which was proved by WAXS investigations. Glass transition temperatures in the range of 62 – 163°C were observed for semicrystalline or amorphous polymers. All aromatic polyformamidines are thermally stable in nitrogen up to 300°C.     

Copolymers of N-vinylcarbazole with monomers containing carboxylic acid groups or carboxylic anhydride groups. I

N-Vinylcarbazole has been copolymerized with olefinic monomers possessing carboxylic acid or carboxylic anhydride functionality to yield copolymers with associated solubility in aqueous alkaline media. The copolymers were prepared to be part of a photoconductive lithographic printing plate assembly. The composition of the copolymers and the reactivity ratios have been evaluated. Copolymerization mechanisms are discussed. Alkali solubility has been measured in terms of the decoating speeds of films of the copolymers from aluminum plates. The major aim of producing an alkali-soluble copolymer that retained the photoconductive properties associated with poly(N-vinylcarbazole) was achieved in part.