Graft Copolymerization of Acrylamide on Swollen poly (Ethylene Terephthalate) Fibers Using Cerium Ammonium Nitrate Initiator

Abstract

In this study the graft copolymerization of acrylamide (AAm) on swollen poly(ethylene terephthalate) (PET) fibers using cerium ammonium nitrate (CeAN) initiator was investigated. Five organic solvents, dimethylsulfoxide (DMSO), morpholine, acetic acid (HAc), n-butanol, and 1,2-dichloroethane (DCE), were used as swelling agents. DMSO was found to be the most suitable swelling agent. Solvent diffusion into the fibers was observed to increase with treatment time and temperature. The optimum graft yield was obtained when fibers were grafted after having been swollen in DMSO for a period of 1 hour at 140°C. Variation of graft yield with polymerization time and temperature, and monomer, initiator, and acid concentrations were investigated. Graft yields were observed to increase initially with polymerization time, then to level off, and were found to increase up to a certain monomer and Ce⁴⁺ concentration, then to decrease slightly. The effect of grafting on such fiber properties as diameter, viscosity, and moisture gain were also investigated.     

壳聚糖-丙烯酰胺接枝共聚及其絮凝性能

壳聚糖-丙烯酰胺接枝共聚及其絮凝性能;壳聚糖;丙烯酰胺;接枝共聚;絮凝     

聚丙烯纤维辐射接枝进展

本文对聚丙烯纤维的辐射接枝方法、特征和机理、以及其研究进展和表征进行了扼要综述。     

Radiation Graft Copolymerization of n-Butyl Acrylate on Natural Rubber Latex

Abstract

A method of radiation graft copolymerization of n-butyl acrylate (NBA) on natural rubber (NR) latex has been studied. The rate of conversion increases with the increase of NBA in latex. An irradiation dose of about 12 kGy is needed to obtain 90% conversion with 40 phr of NBA in latex. Tensile strength, tear strength, and elongation at break of grafted NR are found to decrease with increasing degree of grafting. The physical strength of a vulcanizate prepared from a mixture of NR and ply-NBA was found to be better than that of NBA-NR graft copolymer vulcanizate. The graft copolymerization reaction takes place in the outer layer of NR particles, and because the secondary bonds between poly-NBA molecules may be weaker than those between NR molecules, the existence of a poly-NBA layer in NR particles will decrease its physical strength.     

尼龙-66与衣康酸的接枝共聚反应

以过硫酸钾／硫酸为引发剂,使尼龙-66纤维与衣康酸进行接枝共聚。研究了尼龙-66纤维接枝率与硫酸浓度、过硫酸钾浓度、衣康酸浓度、反应温度、时间和预处理时间之间的关系。实验结果表明,硫酸浓度为0．5mol／L,反应温度50℃,反应时间40h时,接枝率较高,预处理时间对接枝率也有较大影响。     

丙烯酰胺-N-羟甲基丙烯酰胺反相乳液共聚合

：以Ｓｐａｎ ４０ 为乳化剂,过硫酸铵为引发剂,进行了丙烯酰胺 Ｎ 羟甲基丙烯酰胺反相乳液共聚反应,研究了反应温度、单体浓度、引发剂浓度、乳化剂浓度等因素对聚合动力学的影响,并讨论了其聚合机理。     

Graft Copolymerization of Methyl Methacrylate on Poly(phenyl Vinyl Sulfide)

Graft copolymer of poly(phenyl vinyl sulfide) and methyl methacrylate was obtained. The isolation of graft copolymer was carried out by the fractional precipitation method. The isolated polymer was confirmed to be a graft copolymer by IR spectra and T determinations. Graft copolymerizations of poly(phenyl vinyl sulfide) with vinyl acetate, acrylonitrile, acrylamide, and acrylic acid were also carried out, but the separation of graft copolymer in these cases was difficult, and satisfactory results could not be obtained.     

Studies on Copolymerization of Acrylamide and N-Vinylpyrrolidone

Abstract

Copolymers of acrylamide and N-vinylpyrrolidone were prepared using different techniques, viz., solution, precipitation, and inverse emulsion. Xylene was used as a continuous medium and sorbitane monooleate as a surfactant for the inverse emulsion technique. Acetone was used as a solvent in the precipitation technique. The initiator used in all the reactions was 2,2-azobis(2-amidinopropane)dihydrochloride. C, H, and N elemental analysis was used to determine the compositions of the copolymers formed. Reactivity ratios as determined by the Fineman and Ross method were found to be 0.61 and 0.05 for acrylamide and n-vinylpyrrolidone, respectively. Intrinsic viscosity measurements were made at temperatures ranging from 16 to 75°C.     

乙烯吡咯烷酮对PET薄膜的表面接枝改性

利用低温等离子体和UV诱导技术,制备具有较高生物相容性和亲水性的聚对苯二甲酸乙二醇酯(PET)-聚乙烯吡咯烷酮(PNVP)复合膜。利用衰减全反射傅里叶红外光谱(ATR-FTIR)、X射线光电子能谱(XPS)、原子力显微镜(AFM)对PET-PNVP复合膜表面的结构形态进行了系统表征,对影响接枝度的因素如引发剂浓度、UV辐射时间、单体浓度也做了系统分析。润湿性分析结果表明,接枝PNVP的PET膜表面亲水性得到了有效改善。体外血液相容性实验表明PET-PNVP复合膜具有较好的血液相容性。噻唑蓝比色法(MTT法)细胞毒性实验表明,PETPNVP复合膜没有细胞毒性。     

纤维素与己内酰胺的接枝共聚反应

以过硫酸铵和过硫酸钾为引发剂,在碱性环境下进行纤维素与己内酰胺的接枝共聚反应.采用红外光谱仪(FT-IR)、扫描电子显微镜(SEM)及X射线衍射仪(XRD)对接枝共聚物的分子结构、表观形貌和结晶性进行了表征.通过单因素实验重点考察了单体用量、引发剂浓度、反应温度和反应时间等对接枝共聚物接枝率的影响.结果表明:以3 g纤...     

Radiation Graft Copolymerization of a Mixture of Styrene and n-Butyl Acrylate on Natural Rubber Latex

The radiation graft copolymerization of a mixture of styrene (St) and n-butyl acrylate (NBA) monomers on natural rubber (NR) latex has been studied. An irradiation dose of about 18 kGy was needed to attain a conversion of about 80%. The tensile strength of the grafted NR film increases with increasing irradiation dose. A film tensile strength of about 155 kg/cm² was attained by irradiation of a mixture of St, NBA, and NR latex with a dose of about 14 kGy. At low concentrations of monomer in the latex, the Mooney viscosity of the film increases with increasing irradiation dose. At higher monomer concentration, grafting and homopolymerization proceed more favorably than crosslinking, and thus the Mooney viscosity decreases with increasing dose. Thermal analysis of the film showed that the grafted NR was more heat resistant than ungrafted NR.     

CPE—g—MMA共聚物（MC）的合成

MC是以氢化聚乙烯（CPE）为母体，甲基丙烯酸甲酯（MMA）为支链的接校共聚物．由于MC主链为饱和链，与MBS（聚了二烯-g-MMA-苯乙烯接技共聚物）相比在耐老化性等方面有较大的改进．由于聚甲基丙烯酸甲酯（PMMA）与聚氯乙烯（PVC）具有较好的相容性，并对PVC有增初作用，因此MC不仅可作为PVC的增韧剂，还可作为PVC-CPE体系的增容剂．很大程度改善了PVC与CPE间的相容性，使产物的机械性能大幅度提高，并大大降低增韧剂用量[1]．MC的合成方法有多种[1.2]．我们采用自由基型水相悬浮聚合体系合成法．考察了反应时间、反应温度…     

UV-induced Self-initiated Graft Polymerization of Acrylamide onto Poly(ether ether ketone)

Photo-grafting of hydrophilic monomer was used to enhance the hydrophilicity of poly(ether ether ketone) (PEEK) with the aim of extending its applications to biological fields. PEEK sheets were surface modified by grafting of acrylamide(AAm) with ultraviolet(UV) irradiation in the presence or absence of benzophenone(BP). The effects of BP, irradiation time and monomer concentration on the surface wettability of PEEK were investigated. Characterization of modified PEEK using scanning electron microscopy(SEM), energy-disperse spectrometer(EDS) and water contact angle measurements shows that AAm was successfully grafted on PEEK surface both in presence and absence of BP. With the increase in irradiation time and monomer concentration, contact angles decrease to as low as 30°, demonstrating a significant improvement of surface hydrophilicity. In agreement with the decrease in contact angle, under identical conditions, the nitrogen concentration increases, suggesting the increase in grafting degree of the grafting polymerization. This investigation demonstrates a self-initiation of PEEK due to its BP-like structure in the backbone of the polymer. Though the graft polymerization proceeds more readily in the presence of BP, the self-initiated graft polymerization is clearly observed.     

Graft Copolymerization of Acrylonitrile on Bleached Holocellulose

The mechanism by which ceric ions interact with cellulosic materials in the presence of vinyl monomers to initiate graft copolymer formation is generally believed to involve propagation by radicals generated on the cellulosic substrate [1–5]. However, the relatively high levels of homopolymerization and low efficiencies of grafting associated with graft copolymerization suggest that loci of initiation other than radicals formed on the cellulosic materials may be important in graft copolymerization [6].     

蛋白质接枝共聚研究进展

接枝共聚是一种有效的化学修饰方法,经过接枝改性后,高分子化合物的物理、机械和化学性质都能得到改善。文章从引发体系、接枝单体两个方面综述了酪蛋白和丝素蛋白的接枝共聚改性机理以及接枝产物的结构和性能。接枝反应中引发剂浓度和接枝单体浓度都有一个最佳值,接枝产物的热性能和力学性能都有所提高。     

Copolymerization of N-Vinyl-4,5,6,7-tetrahydroindole with Acrylamide

Radical copolymerization of N-vinyl-4,5,6,7-tetrahydroindole with acrylamide in dimethylformamide was studied, and the relative activity constants of the monomers were determined.     

Microwave Assisted Graft Copolymerization of N-Isopropyl Acrylamide and Methyl Acrylate on Cellulose: Solid State NMR Analysis and CaCO3 Crystallization

Summary: Graft copolymerization of N-isopropyl acrylamide and methyl acrylate on α-cellulose was carried out under microwave irradiation at specific cut off temperatures with cerium (IV) ammonium nitrate and potassium persulfate (KPS) as the initiating system. The role of KPS was to oxidize Ce (III) to Ce (IV) which is the active species in radical formation. The reactions at a temperature cut off of 60 °C were confirmed by ¹³C nuclear magnetic resonance cross-polarization with magic- angle spinning (¹³C NMR CP/MAS) and Fourier-transform infrared spectroscopy (FTIR). The extent of grafting was calculated from weight gain and ¹³C resonances. The grafted cellulose was thermally more stable than the parent cellulose. An attempt to do grafting at a higher cut off temperature of 80 °C was made, however, no grafting was observed from ¹³C NMR CP/MAS but TGA results showed that a cellulose having more thermal stability resulted which was attributed to cross linking. Crystallization of CaCO₃ was carried out using the grafted materials as templates showed better nucleation and different crystal structure was observed.     

(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺反相微乳液共聚合特性研究

选用SPAN80与OP10复合乳化剂、K₂S₂O₈-Na₂SO₃氧化还原引发剂,进行(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺反相微乳液共聚合反应.研究了单体配比、电解质浓度和乳化体系的油水比对共聚物分子量及离子度的影响,考察了该共聚合体系的反应特性.     

过硫酸铵-尿素引发丙烯酸甲酯与明胶接枝共聚

接枝共聚合反应;过硫酸铵-尿素引发丙烯酸甲酯与明胶接枝共聚