聚氯乙烯接枝丙烯酸稀土的研究

将无机稀土有机化后与聚氯乙烯(PVC)进行接枝共聚。探讨了氧化稀土与丙烯酸反应、PVC接枝丙烯酸稀土的原理和方法，并通过红外光谱、扫描电镜对接枝共聚物进行定性表征，用微量热天平对接枝共聚物的热性能进行测定。实验结果表明，经丙烯酸稀土接枝共聚后的PVC，其耐热分解性能和韧性有了明显的提高。     

含季铵基离子交换纤维的制备研究

以辐射接枝丙烯酸(AA)后的聚丙烯(PP)无纺布(PP-g-AA)为基材,采用紫外引发的方法接枝甲基丙烯酰氧乙基三甲基氯化铵(DMC),建立了一种制备阴离子交换纤维的新方法,得到了PP-g-AA-DMC纤维.研究了丙烯酸接枝率、DMC浓度、溶剂种类、光照时间,浸泡时间等因素对DMC接枝率的影响,结果表明,DMC的接枝率随着丙烯酸接枝率、DMC浓度、光照时间和纤维浸泡时间的增加而增大.接枝前后纤维的红外光谱分析表明,DMC被成功接枝在PP-g-AA基材上.吸附性能测定结果表明,纤维对水中以阴阳离子存在的金属铬均具有较好的吸附性能.     

聚烯烃纤维表面光接枝的ESCA表征

以320—440nmUV为光源,二苯甲酮(BP)为光引发剂,丙烯酸(AA)和丙烯酰胺(AM)为单体,在高强度聚乙烯(HSPE)纤维上进行光引发接枝反应。由于纤维,表面接枝仅发生在小于50A的极薄层内,这样的表面接枝率不可能用通常的称重法测定,因而无法用通常意义的重量接枝率来表征。本文对表面接枝纤维用X射线光电子能谱(ESCA)进行分析测试,以谱中氮(或氧)原子1s内壳层电子和碳原子1s内壳层电子谱线的积分强度相对比值来表征接枝程度。傅里叶红外(FTIR)内反射光谱的测试结果,以及对接枝纤维进行的染色性和粘接性测试表明,用ESCA的上述积分强度相对比值(RI％)来半定量表征接枝程度是合宜的。     

甲基丙烯酸丁酯接枝纤维素的制备

为开发纤维素基吸油材料,以棉浆粕为基材、甲基丙烯酸丁酯(BMA)为单体、乙二醇二甲基丙烯酸酯为交联剂,采用悬浮接枝聚合法合成了BMA接枝纤维素的聚合物。采用红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM)、热重(TG)、差热(DSC)等手段对所得吸油材料结构进行了表征。考察了引发剂的种类及用量、接枝单体及交联剂用量、反应温度、反应时间等因素对BMA接枝纤维素聚合物的接枝聚合反应性能及吸油性能的影响。结果表明:当m(棉浆粕)∶m(K2S2O8)∶m(BMA)∶m(乙二醇二甲基丙烯酸酯)=1∶0.025∶1.5∶0.005,75℃下恒温反应6 h,合成的BMA接枝纤维素的接枝率最高(36.2%),均聚物含量相对较低(5.8%),且吸油性能优良。     

PVA-SiO_2复合物改性棉纤维及其吸油性能

首先以棉纤维为主要原材料,通过一步浸渍将聚乙烯醇-二氧化硅粒子(PVA-SiO_2)复合物涂覆在棉纤维表面;然后对其进行疏水改性,制得一种超疏水吸油材料。通过扫描电子显微镜(SEM)和水接触角(WCA)测试对改性纤维的表面结构及润湿性进行了分析表征。研究了PVA和SiO_2纳米粒子的质量分数对纤维吸油性能的影响,并评价了改性纤维的疏水性、润湿耐受性、吸油速率和重复使用性能。结果表明:棉纤维经过PVA-SiO_2复合物涂覆后具有稳定的超疏水性,吸油量比改性前显著提高,对正己烷、甲苯和氯仿的吸油量分别提高了47%、18.6%和26.2%。     

抗菌水凝胶敷料的制备及性能

以乙二醇二缩水甘油醚(GDE)为偶联剂,将胍盐低聚物(PHMG)接枝到淀粉上,形成淀粉接枝物(Starch-g-PHMG)。然后,将一定比例的Starch-g-PHMG与淀粉-丙烯酸接枝共聚物共混,制备了抗菌水凝胶敷料(AHD)。通过红外光谱(FT-IR)、元素分析确定了Starch-g-PHMG的分子结构;通过吸液测试、抗菌测试表征了AHD的理化性能。结果表明:在反应温度为60°C,反应时间为3h,w(NaOH)=0.4%时,Starch-g-PHMG中PHMG的接枝效率最高,可达37.5%;AHD的吸液率随着Starch-g-PHMG含量的增加而减少;当w(PHMG)0.33%时,AHD对金黄色葡萄球菌与大肠杆菌的抑菌率可以达到100%。     

一种新型的亲水性聚丙烯酸-陶瓷复合膜

通过化学气相沉积和丙烯酸(AA)在大孔陶瓷膜表面的接枝共聚制备了一种新型的亲水性PAA-陶瓷复合膜. 用FT-IR、SEM、EDS、表面接触角等方法对复合膜接枝层的化学组成、表面形态、元素分布和亲水性进行了表征. 通过系统研究气相沉积和接枝反应的主要条件对膜的渗透汽化性能的影响, 发现当TEOS用量为5 mL, 汽化温度为175 ℃时进行气相沉积, 然后在丙烯酸浓度为7.5%的溶液中进行接枝聚合, 制得的复合膜对醇水混合物显示了优良的分离性能.     

芴酮引发光接枝改性LDPE膜的研究

采用紫外光引发接枝表面改性的方法,以芴酮(FL)为引发剂,在低密度聚乙烯(LDPE)薄膜表面上接枝丙烯酸(AA)、甲基丙烯酸(MAA)、丙烯酸甲酯(MA)、甲基丙烯酸甲酯(MMA)、丙烯酰胺(AM)等单体,以赋予薄膜表面新的化学性质.考察了引发剂浓度、紫外光的辐照时间、辐照强度、单体种类对LDPE薄膜接枝程度的影响.结果表明,在一定范围内,增加芴酮浓度,可以提高单体的接枝率,但当芴酮浓度达到5%时,接枝率反而下降.延长辐照时间至4 min和提高紫外光的辐照强度达100 W/m2,均有利于接枝反应的进行.不同单体在LDPE膜上的接枝能力与单体的活性、单体与基材的相容性等因素有关.接枝后,LDPE与水的接触角下降程度不仅与单体在膜上的接枝量有关,还与接枝单体的亲水性能密切相关.     

聚砜与丙烯酸的紫外光辐射接枝共聚及其表征

在均相溶液体系下,运用紫外光辐射引发合成了聚砜与丙烯酸的接枝共聚物。用化学滴定、漫反射傅立叶变换红外光谱和热分析等技术对接枝聚合物进行了表征。结果表明:丙烯酸被接枝在聚砜链上;光照时间、单体浓度和光引发剂浓度对接枝率均有较大影响。膜表面接触角的研究表明,接枝共聚物膜的亲水性比改性前有所提高。     

新型两性聚电解质高吸水性树脂CMCTS-g-（PAA-co-PTMAAC）的制备研究

通过氧化还原引发荆引发的接枝共聚反应,使阴离子型单体丙烯酸(AA)和阳离子型单体三甲基烯丙基氯化铵(TMAAC)在羧甲基壳聚糖(CMCTS)的分子链上接枝共聚,制得羧甲基壳聚糖接枝-(聚丙烯酸-co-聚三甲基烯丙基氯化铵)(CMCTS-g-(PAA-co-PTMAAC)两性聚电解质高吸水性树脂.采用红外光谱对产物的结构进行了表征,比较了反应条件对产物吸液性能的影响.发现制备具有良好吸液性能的高吸水性树脂的最优化反应条件为:TMAAC占单体总质量的14.3%,mNNMBA/mAA值在0.014附近,单体总质量为CMCTS质量的9.33倍,丙烯酸中和度在20%～30%之间.研究发现,随外部溶液pH值的变化,两性聚电解质高吸水性树脂的溶胀性能在酸性和碱性条件下各有一个最大值,在等电点处产物的吸液性相对较低.     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).