蛋白质接枝改性腈纶的水解工艺研究

采用NaOH溶液对腈纶进行水解,表面接枝蛋白质制得改性腈纶。讨论了NaOH浓度、水解温度、水解时间对腈纶接枝效果的影响。结果表明:在水解反应温度80~90℃、NaOH溶液质量分数14%、水解时间15 m in时,改性腈纶接枝率较高。力学性能分析和电镜表面观察表明:在腈纶表面接枝大豆蛋白质,不仅可以赋予纤维表面完整的蛋白质覆盖层,而且还可以较好的弥补纤维因水解而产生的表面损伤和力学性能下降等缺陷。     

大豆蛋白质改性腈纶的接枝工艺探讨

采用大豆蛋白质接枝改性腈纶,研究了接枝工艺条件对接枝率的影响。结果表明:在加入过量的蛋白质,加入质量分数10％的NaOH用量为1 mL、反应温度80℃,反应时间5 min,能够获得较好的接枝效果,腈纶表面蛋白质接枝率达3．2％。红外分析表明在腈纶表面接枝蛋白质效果明显。     

水解条件对腈纶吸水性能的影响

对制备高吸水腈纶的水解工艺进行了研究。结果表明,水解时间和温度以及氢氧化钠浓度都对腈纶的吸水率有影响。水解时间越长,水解温度越高,纤维的吸水率越大,但其外观与机械性能将变差,氢氧化钠浓度在10％左右时纤维的吸水率出现最大值。水解的适宜条件:氢氧化钠浓度8％～12％,水解时间10～12min,水解温度80～90℃。     

腈纶表面接枝蛋白质改性的基本工艺过程与效果

论述了腈纶表面接枝大豆蛋白质的基本工艺过程与效果,结果表明:腈纶经过表面水解、酰氯化、接枝反应等几个简单步骤就可以接枝上大豆蛋白质表面覆盖层,从而达到对腈纶进行蛋白质化学改性的目的。SEM观察表明:接枝之后,蛋白质将会填充腈纶的表面裂纹与微孔,赋予纤维以新的结构形态。     

高吸水腈纶纤维的研制

用碱减量法对腈纶纤维进行表面改性，控制碱浓度为8％，水解时间为10分钟，水解温度为90℃，可以得到吸水率达54％的高吸水腈纶纤维。     

淀粉接枝丙烯腈合成高吸水树脂的工艺研究

以淀粉接枝丙烯腈制备高吸水树脂(SAP)。考查了丙烯腈用量、引发剂用量、聚合时间、聚合温度、水解时间对产品纯度及吸水率的影响。结果表明,合成SAP的最佳工艺条件为:丙烯腈用量10.5 g,为淀粉用量的3.5倍,引发剂用量0.08 g,占淀粉用量的2.67%,聚合时间2.5 h,聚合温度30℃,水解时间2.5 h。甲醇作沉淀剂,调整冷却速度,合成树脂吸水率达1 200倍以上。     

紫外辐射接枝改性UHMWPE纤维表面的研究

采用紫外辐射接枝方法对超高相对分子质量聚乙烯(UHMWPE)纤维表面进行改性。探讨了单体种类及浓度、引发剂、抗氧剂、接枝方法等对UHMWPE纤维表面处理效果的影响,测试了以其作为增强材料的复合材料的层间剪切强度。结果表明:在有氧开放体系下,气相接枝效果好于液相接枝;丙烯酰胺单体的接枝效果优于其它单体;接枝率随接枝单体浓度和接枝时间的增加而增加。采用丙烯酰胺为接枝单体,在光强度为86μW/cm~2条件下,对UHMWPE纤维进行紫外辐射接枝改性,按照一定铺层方式制备的环氧基复合材料的层间剪切强度从未处理的14.59MPa提高到17.36MPa。     

对腈纶废丝碱法水解产物接枝后絮凝性能的研究

腈纶废丝在常压碱性条件下水解后,与二甲胺进行接枝制备絮凝剂的适宜条件为:NaOH、水、二甲胺用量分别为14 g、160 mL、36 g,接枝温度为90℃,在此条件下制得的絮凝剂对废水的除浊效果可达到92%以上。     

粘胶纤维接枝共聚研究

用高锰酸钾为引发剂 ,将粘胶纤维与丙烯酸接枝共聚 ,研究了接枝共聚反应工艺条件对接枝率的影响。结果表明 :高锰酸钾浓度 ,预处理温度、时间 ,硫酸浓度 ,丙烯酸浓度 ,反应温度、时间均与接枝率有关 ,反应中选择高锰酸钾浓度 0 .0 7mol/ L ,预处理温度 5 0℃、时间 2 0 min,硫酸浓度 0 .0 8mol/ L ,丙烯酸浓度 1.2 m ol/ L ,反应温度 90℃ ,粘胶纤维接枝率可高达 72 %。     

三叶异形聚酯共混纤维的碱水解性能

将PET与易水解聚酯(EHDPET)质量比80：20的三叶异形共混纤维进行碱(NaOH)水解处理,探讨了NaOH浓度、渗透剂浓度、水解时间等影响因素。结果表明：渗透剂浓度对共混纤维碱减量率的影响最大,其次分别是NaOH浓度、水解时间、处理温度。其中渗透剂浓度约0．05g/L较好,最大碱减量率应控制小于25%。电子显微镜照片表明随着碱减量率增加共混纤维表面微沟槽逐渐加深,三叶逐渐破裂分离。     

Surface modification of polyacrylonitrile (PAN) fibers by grafting of natural polymer-soybean protein (SP)

Summary A novel method of modifying polyacrylonitrile (PAN) fibers by grafting of soybean protein (SP) onto it was studied. The reactant of PAN-g-SP fiber was prepared based on chlorination of the hydrolyzed PAN fiber. The effects of chlorination and grafting conditions on the grafting efficiency were investigated. The grafting efficiency first increases with the increase of the addition of thionyl chloride (SOCl₂), chlorination time and temperature and then levels off. In grafting reaction, grafting efficiency increases at first and then declines significantly with increasing addition of sodium hydroxide (NaOH), grafting temperature and time. The grafted polymer was characterized by FT-IR spectroscopy, X-ray diffraction and SEM images. The results indicated that SP was grafted onto the PAN fiber. PAN-g-SP also exhibits good hygroscopicty and proper mechanical properties.     

Photoinitiated surface grafting of synthetic fibers,I. Photoinitiated surface grafting of ultra high strength polyethylene fibers

Photoinitiated surface grafting of acrylic monomers has been carried out onto high strength polyethylene (HSPE) yarn by means of a continuous process. The grafting reaction is initiated by UV irradiation of the yarn after presoaking in an acetone solution of initiator and monomer. Four initiators, benzophenone (BP), 4-chlorobenzophenone (4-CBP), 2-hydroxy-2-cyclohexylacetophenone (HHA), and 2,2-dimethoxy-2-phenylacetophenone (DMPA), and two monomers, acrylic acid (AA) and acrylamide (AM), have been used. After short irradiation time (10 to 20 s) successful grafting is obtained, as shown by ESCA and IR-ATR spectra, dye adsorpotion from aqueous solution, and measurements of adhesion of single filaments to epoxy resin. Grafting efficiency of 74% has been reached for AA as monomer (26% is homopolymer). The tensile strength and modulus of the HSPE yarn are retained in the grafting process. The degree of surface grafting is mainly a function of structure and concentration of monomer and photoinitiator in the presoaking solution and of the irradiation conditions used. Increasing irradiation time gives increasing amounts of grafted polymer up to a certain limiting value. The reactivities of the four initiators have been compared showing the highest grafting yields of AA with BP and of AM with 4-CBP as photoinitiator. AA grafted HSPE yarn can be dyed to rather deep color by dipping in an aqueous solution of Crystal Violet. Increased dye absorption by a factor of up to seven has been measured for yarn grafted with AA to the maximum level obtained. The filaments of the grafted yarn show increased adhesion to epoxy resin by a factor of up to five compared with the ungrafted filaments.     

微乳液法腈纶接枝聚苯胺及其性能研究

采用低温等离子体技术对腈纶纤维表面进行处理,使用苯胺微乳液在腈纶表面进行接枝聚合,对腈纶进行改性处理,通过增重率、导电率测试、接枝聚合的因素和接枝聚合对腈纶纤维结构、导电性能和强力进行分析评价;扫描电镜和红外测试显示聚苯胺成功接枝上腈纶表面;腈纶接枝聚苯胺后,导电性能增加,强力变化不大,但伸长率略有降低。     

马来酸酐固相接枝聚丙烯纤维

了提高非极性聚丙烯纤维(PP)的相容性,采用固相法以马来酸酐(MAH)对聚丙烯纤维进行接枝改性,研究了反应条件对接枝率的影响。结果表明,马来酸酐成功接枝到聚丙烯上,当反应温度为80℃,PP用量为0.5 g,MAH用量为0.2 g,BPO用量为0.05 g,回流时间为2.5 h时,最大接枝率可达到7.51%;BPO的用量、MAH单体的用量以及反应温度对PP纤维的接枝率影响较大。而测定PP纤维接枝率时回流时间对其接枝率的影响不大;接枝聚丙烯纤维的分解温度明显高于纯聚丙烯纤维。     

Radiation grafting of acrylic and methacrylic acid to cellulose fibers to impart high water sorbency

Acrylic and methacrylic acids have been directly grafted to rayon and cotton using the preirradiation technique with ⁶⁰ Co γ rays. The rate of grafting increased with increasing temperature and monomer concentration, as did the final degree of grafting. The amount and rate of grafting also increased with the total irradiation dose but tended to level off at higher doses, in agreement with the leveling off of the radical content reported previously. Methacrylic acid grafted more and faster than acrylic acid to both rayon and cotton. Methacrylic acid grafted more with rayon than cotton, but acrylic acid gave somewhat similar yields with both fibers. The water absorbency of the grafted fibers depended strongly on their posttreatment. Decrystallizing with 70% zinc chloride or with hot sodium hydroxide developed supersorbency. The two treatments in succession, respectively, gave the highest values. Methacrylic acid brought about less sorbency than the corresponding acrylic acid grafts. Useful levels of grafting and supersorbency could be readily and practically achieved by the methods described.     

Modification of polyolefin surfaces by plasma-induced grafting

Polar monomers have been grafted onto polyolefin surfaces with the aid of inert gas plasma. In the first stage, an inert gas plasma (argon plasma) was used to generate free radicals on the polyolefin surface. In the second stage, the plasma generator was turned off and a vinyl monomer introduced as a vapor. Monomer was surface grafted by free radical polymerization. After cleaning and drying, the samples were analyzed by XPS, IR, and contact angle. LD–PE was successfully grafted with acrylic acid, glycidyl methacrylate, methyl acrylate, and 2-hydroxy ethylacrylate. The grafting of acrylic acid was studied in more detail, and the rate of grafting was observed to increase with increasing monomer pressure and to decrease with time. The increasing of grafting temperature was found to reduce the degree of grafting. This last factor can be explained by the reduced concentration of monomer at the polymer surface or by a deactivation of surface radicals. © 1996 John Wiley & Sons, Inc.     

Study on the Graft Reaction of Poly(propylene) Fiber with Acrylic Acid

Summary: In this paper, the graft of poly(propylene) fiber with acrylic acid is investigated. The effects of grafting temperature, monomer concentration, and grafting time on the grafting degree of acrylic acid onto poly(propylene) fiber are discussed. In contrast to the conventional method of determining the grafting degree gravimetrically, the acid‐base titration method used in this paper was more efficient, even at low grafting degree. High‐performance liquid chromatography (HPLC) was used to estimate the averaged length of the grafted poly(acrylic acid) chains on each grafted site of poly(propylene) backbone. And also a mechanism for the grafting polymerization is proposed.

Possible microstructures of two PP‐g‐AA samples at the same grafting degree.     

Photoinitiated surface grafting of synthetic fibers,III. Photoinitiated surface grafting of poly(ethylene terephthalate) fibers

Photoinitiated surface grafting of acrylic acid (AA), acrylamide (AM) and 4-vinyl pyridine (VP) onto poly(ethylene terephthalate) (PET) fibers (a commercial textile yarn) has been studied using benzophenone (BP) as photoinitiator. A continuous process as previously described has been applied, which involves presoaking of the PET yarn in a solution of initiator and monomer in acetone and UV irradiation in nitrogen atmosphere. The resulting grafted polymer on the fiber surface has been analyzed by ESCA, titration of carboxy groups (grafted AA), and dye absorption. The relative ESCA intensities (RI) of O1s/C1s and N1s/C1s are used as measure for grafted AA, AM and VP, respectively, after recording the RI-values for ungrafted fibers. For grafting with AA, the RI-values increased from 32.8% (background) to 48.6% after 20 s irradiation time. The amount of carboxy groups measured by titration increased from 0.045 to 0.106 mmol/m². Assuming an even coverage of grafted AA polymer, this means a grafted layer of 4.8 nm thickness. After grafting, the adsorption of the dye Crystal Violet (CV) from aqueous solution increased by about 3 times. With AM as monomer, the RI-values increased from 2.6 (background) to 14.8% and the adsorption of a direct dye Sirius Lichtbordo B-LL increased by about 6 times. With VP as grafted monomer, the RI-values increased from about 2.6 (background) to 5.1% and the adsorption of the direct dye increased by about 4 times.     

Kinetics study of radiation‐grafting of acrylic acid,acrylonitrile, and their mixture onto wool fabric

The effect of monomer concentration, exposure time, irradiation temperature, and weaving direction on the kinetics of grafting acrylic acid (AA), acrylonitrile (AN), and their mixture onto wool fabric has been studied at the dose rate of 1.38 Gy/s. The degree of grafting is found to depend on the methanol‐to‐water solvent ratio and fabric‐to‐liquor ratio. The grafting rate and rate constant are dependent on irradiation temperature, type of grafted monomer, and weaving direction. The grafting rates increase with the increase in irradiation temperature (276–308 K). The calculated activation energy is nearly the same (16.4–17.2 kJ mol^?1) and the preexponential rate constant is dependent on the type of grafted monomer. The grafting of AA, AN, and their mixture are confirmed from the dyeing affinity of grafted fabrics towards Sandocryl Blue (SB), a basic dye. The formation of wool grafts and structural changes resulting from grafting were verified by using FTIR spectrometry and X‐ray diffraction analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4328–4340, 2006     

Improving the hydrophilicity of polyethersulfone membrane by the combination of grafting technology and reverse thermally induced phase separation method

In this work, surface grafting modification technology was combined with reverse thermally induced phase separation (RTIPS) method in order to improve the structure and permanent hydrophilicity of polyethersulfone (PES) membranes. Acrylic solution with different concentrations was grafted on the surface of PES membranes while grafting temperature and grafting time were also varied. The modified PES membranes were characterized in all aspects. Attenuated total reflectance Fourier transform-infrared confirmed successful modification of the PES membrane by grafting acrylic acid. Scanning electron microscopy revealed that homogeneous porous top surface as well as spongy-like cross-section structure appeared in the membrane by RTIPS procedure. Moreover, porosity was affected by changes of acrylic acid concentration, grafting temperature, and grafting time. Atomic force microscopy showed that grafting acrylic acid gave a reduction in roughness of PES membrane. Combined with the decreased values of contact angle, the hydrophilicity and antifouling performance of the PES membrane were improved. The pure water flux and BSA rejection rate of the grafted PES membranes were remarkably improved for pure PES membrane and attained a maximum, which was 1,646.24 L/(m²h) and 94.5%, respectively. The long-term test demonstrated that grafting membranes exhibited outstanding elevated water flux recovery ratio (>85%).