AbstractA range of starch-g-poly (2-hydroxyethyl acrylate) (S-g-PHEA) with different grafting ratio was prepared by graft copolymerization of 2-hydroxyethyl acrylate (HEA) onto granular cornstarch using ammonium cerium nitrate as initiator. The adhesive ability of the sizes to cotton fibers, film properties, and desizing ability of HEA branch grafted onto starch were investigated. The effects of grafting conditions (such as reaction time, temperature, HEA and initiator concentration, etc.) on grafting ratio and efficiency were investigated. Fourier transformed infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA) was employed to characterize the complexes of S-g-PHEA. The effect of grafting ratio on the sizing properties of grafted starch was studied by testing the ability of the grafted starch to adhere to cotton fiber and film properties. It was confirmed that the HEA branch can effectively improve the adhesion ability of starch to cotton fibers, improves the flexibility of the starch film while reduces the brittleness, and enhances the abrasion resistance of the yarns (the highest enhancement ratio up to 225.71%). An increase in the grafting ratio facilitates the adhesion to the cotton fibers while making the desizing difficult. The desizing efficiency was high when the grafting ratio was less than 10%, which lead to easy access to desizing and then fewer residues have remained, and at the same time, good sizing performance is maintained, which indicates that the S-g-PHEA possesses the application potential of cotton warp sizing. 相似文献
The effect of concentration, reactant ratios, temperature, and starch pretreatment on grafting of acrylonitrile onto starch were studied. Grafting was efficient at high concentrations (8–12% starch) when granular starch was used. The molecular weights for grafted polyacrylonitrile (PAN) were higher when gelatinized starch was used, but grafting efficiencies (grafted PAN/total PAN) were much lower. The molecular weight of the grafted side chain increased with increased concentration of reactants. The grafting frequency was highest when the reaction mixture was kept at 5°C and decreased with increased swelling of the starch. The starch–polyacrylonitrile graft copolymers were saponified and dried to give products which absorbed 75–440 ml H2O per gram and 20–70 ml synthetic urine per gram. 相似文献
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. 相似文献
The incompatibility of hydrophilic wood fiber and hydrophobic polymers is the main difficulty with wood thermoplastic polymer composites. To overcome this issue, many researchers suggest grafting polymer onto wood fiber for improving the interfacial adhesion during mixing. A systematic ESCA study of chemi-thermo-mechanical pulp (CTMP) grafted fiber has been performed to provide chemical information about surface composition modification. The material analyzed included initial CTMP fiber, the pure polymer i.e., poly(methyl methacrylate) (PMMA) as reference material, and grafted fiber at different polymer loadings. Interest is focused on the carbon and oxygen spectra. Samples at high polymer loading or high grafting level have an O/C, C1, C2, C4, O1, and O2 intensities much similar to those of the PMMA but a little different since some wood fiber sites have still not fixed the polymer. ESCA spectra provide information on about 1–5 nm depth. The ESCA technique allows the monitoring of grafting polymer onto wood fiber as a surface phenomenon. 相似文献
Acrylonitrile (AN) has been grafted onto Polyvinylchloride (PVC) dissolved in Dimethylformamide (DMF) by means of gamma rays from a Co60 source. The grafting yield has been studied as a function of irradiation dose and initial AN/PVC ratio in the solution.
The ratio PAN/PVC has been evaluated both in the grafted copolymer and its fractions by infrared spectroscopy. Ultrafiltration membranes have been prepared from the grafted PVC and its fractions, using the phase inversion technique.
The UF performances have been studied as a function of PAN grafted %.
The results show that both water flux and rejection increase with the grafting. Electron microscopy has also been employed to investigate the membrane structure. 相似文献
Graft copolymerization of methyl acrylate (MA) onto OPEFB fiber has been successfully carried out using hydrogen peroxide and ferrous ammonium sulfate as initiators in an aqueous medium. The effects of reaction temperature, reaction period, and amount of monomer and initiators on the percentage of grafting were investigated. The results show that the percentage of grafting depends on reaction period and temperature as well as concentration of monomers and initiators. With 33.36 mmol of MA, the optimum percentage of grafting was obtained when the reaction was carried out using 6.00 mmol of H2O2 and 0.191 mmol of Fe2+ for 210 min at 75°C. The presence of the functional group in the grafted polymers was characterized by FTIR spectroscopy. Scanning electron microscopy was used to study the surface morphology. Thermogravimetric analysis indicated that the grafted OPEFB is thermally stable than the OPEFB 相似文献
To prepare a carbon nanotube (CNT)/carbon fiber multi-scale reinforcement (MSR), multi-walled carbon nanotubes (MWCNTs) functionalized at the end caps with hexamethylene diamine (HMD) are grafted onto the surfaces of carbon fibers treated with acyl chloride. The surface element concentrations, surface functional groups and morphology of the MSR were examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XPS spectra indicate that sp2 and sp3 carbon atoms are major components in the MSR surface, and the carbon fiber surface structure is not destroyed. There is 17.41% of C-NHx in the surface of the MSR, which suggests that MWCNTs are covalently grafted onto carbon fiber surfaces. SEM shows that the grafted MWCNTs stick to the carbon fiber surface at different angles, and are uniformly distributed along the outer edges of the grooves in the fiber surface. The grafted MWCNTs are 50-200 nm in length and around 14 nm in diameter. It was found that the grafting increases the weight of carbon fiber by 1.2%, which implied that a considerable amount of MWCNTs were grafted onto carbon fiber surfaces. 相似文献