CMCNa-g-(NVP-co-AM)三元共聚物的合成、表征及性能

以羧甲基纤维素钠(CMCNa)、丙烯酰胺(AM)和N-乙烯基吡咯烷酮(NVP)为原料,过硫酸铵为引发剂,在水介质中制备CMCNa-g-(NVP-co-AM)接枝共聚物,考察不同温度及不同离子强度下接枝共聚物水溶液粘度的流变性能。结果表明,相对于CMCNa-g-AM二元共聚物,在盐水溶液中和高温条件下,CMCNa-g-(NVP-co-AM)粘度保留率均有所提高;聚合物溶液Cr3+交联凝胶的流变实验结果显示,m(NVP)∶m(AM)=1∶5为最优比例,此时的三元共聚物CMCNa-g-(NVP-co-AM)具有更优良的抗温性能。     

羧甲基甲壳素与丙烯酰胺接枝聚合反应研究

制备了羧甲基甲壳素接枝丙烯酰胺共聚物,讨论了反映温度、时间、引发剂用量、溶剂用量、单体用量对接枝反应的影响。最佳反应条件为：羧甲基甲壳素0．4g,溶济水50mL,引发剂60mg,单体1．6g,反应温度50℃,反应时间3．0h。     

丙烯腈接枝羧甲基甲壳素水溶性衍生物的制备和表征

以羧甲基甲壳素和丙烯腈为原料,制备了丙烯腈接枝羧甲基甲壳素衍生物,讨论了反应温度、反应时间、溶剂用量、引发剂用量、单体用量对接枝反应的影响。结果表明,最佳反应条件为:羧甲基甲壳素0.4 g,溶剂水40.0 mL,过硫酸铵50.0 mg,丙烯腈2.5 g,反应温度60℃,反应时间2 h。所制共聚产物具有水溶性,分析了产物具有水溶性的原因。     

1,2‐propanediol–cellulose–acrylamide graft copolymers

1,2‐Propanediol–cellulose–acrylamide graft copolymers (PCACs) were developed for enhanced oil recovery. They were prepared with acrylamide and 1,2‐propanediol (PDO)–cellulose, which was formed through the addition of glycols to cellulose by the Shotten–Baumann reaction between 3‐chloro‐1,2‐propanediol and cellulose. The graft copolymerization was initiated with a redox system between Ce⁴⁺ and glycols in cellulose. The infrared spectrum of PDO–cellulose had some characteristic absorption bands around 2960 (νC? H) and 1050 cm^?1 (νC? O) that also appeared for the PDO group and pyranose ring of cellulose, respectively. The rate of Ce⁴⁺ consumption by PDO–cellulose was investigated through the calculation of the overall kinetic constant from the slopes of ln(D ? D_R) versus time (where D is the absorbance and D_R is the absorbance of the original polysaccharide solution) The results showed that PDO–cellulose had high reactivity and that there were two mechanisms of oxidation by Ce⁴⁺ with PDO–cellulose. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3022–3029, 2004     

Preparation of gelatin–N-vinylpyrrolidone graft copolymer

The graft copolymerization of N-vinylpyrrolidone (VP) onto gelatin was carried out by the following four different initiator systems: AIBN, K₂S₂O₈, H₂O₂—Fe²⁺, and Ce⁴⁺—HNO₃. The last one caused the monomer to lose the double-bond and polymerization ability due to the hydrolysis of the monomer. Using α,α-azobisisobutyronitrile as an initiator, the graft copolymerization of gelatin and N-vinylpyrrolidone in aqueous medium was studied systematically. The relationships between the rate of grafting and the concentration of initiator, monomer, and gelatin were established experimentally. Meanwhile, the rate equation was also derived from the proposed reaction mechanism, and it was similar to the equation previously obtained experimentally. The apparent activation energies for homopolymerization (E_h), graft copolymerization (E_g), and over all polymerization (E_p) were calculated. The graft efficiency and molecular weight of the grafted PVP were measured by hydrolyzing the backbone with hydrochloric acid. The graft copolymers Gel-g-PVP were added into the coating films, and the physical properties of the films, such as hardening ability, dimensional stability, and wetting property were investigated. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1485–1492, 1998     

Preparation and properties of polyethylene–clay nanocomposites by an in situ graft method

The polyethylene–clay nanocomposites were prepared by the in situ graft copolymerization of styrene containing twin‐benzyldimethyldioctadecylammonium bromine modified montmorillonite (TBDO‐MMT) in polyethylene with dicumyl peroxide (DCP) as an initiator in molten state. XRD and TEM analysis indicated that intercalated polyethylene/MMT nanocomposites are obtained. The mechanics performance, crystal behavior, thermal properties, and the effect of MMT contents on PE/MMT nanocomposite were also studied. As comparison, polyethylene/montmorillonite composites prepared by a simply melt compounding without styrene were studied as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4921–4927, 2006     

ATRP法均相制备纤维素/甲基丙烯酸丁酯接枝聚合物

在纤维素LiCl/DMAc均相溶液中,通过氯乙酰氯（ClC₂OCl）与纤维素的均相酰化反应制得纤维素氯乙酸酯（Cellulose-ClAc）后,将其溶解在DMAc中,在FeCl₂/4-二甲氨基吡啶（DMAP）的催化作用下,引发甲基丙烯酸丁酯（BMA）的均相ATRP 聚合反应,制备了纤维素/BMA接枝共聚物（Cellulose-g-PBMA）,考察了反应时间、反应温度、反应物配比等对酰化及接枝聚合反应的影响,并通过测试Cellulose-g-PBMA薄膜的接触角,对最终产物的疏水性能进行了研究;采用FTIR、NMR、SEM、TEM、AFM等分析手段对Cellulose-ClAc及Cellulose-g-PBMA的结构进行了表征;利用GPC分析了接枝聚合反应的活性特征。     

Preparation for graft copolymers of sawdust/vinyl monomers and their application for removal of dye

A kind of cationic exchanging resin of carboxyl sawdust (CSD) was fabricated through the hydrolysis of graft copolymers of sawdust with acrylonitrile (SAN) and sawdust with acrylamide (SAA) that were made by initiator Fe²⁺/H₂O₂. A study of the graft copolymerization was conducted for initiator usage, vinyl monomer usage, and reaction temperature. The hydrolysis under basic/acid conditions was also studied for the yield and acid value of CSD followed to adsorb Basic Pink dye (BPD). Our results show the following: (1) graft copolymers (SAN and SAA) with a high rate of graft copolymerization are readily prepared by suitable usages of initiator and vinyl monomer under a certain temperature; (2) adsorption capacity of CSD is relative to pH of BPD solution and reaches the most adsorption capacity at pH ≈ 6; (3) adsorption capacity of CSD increases along with the augment of its acid value; and (4) the adsorption capacity of the CSD toward BPD increases along with augment of initial concentration of the adsorbate and reaches about 500 mg/g. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2390–2396, 2002     

Ceric(IV) ion‐induced graft copolymerization of acrylamide and ethyl acrylate onto cellulose

Graft copolymerization of acrylamide (AAm) and ethyl acrylate (EA) onto cellulose has been carried out from their binary mixtures using ceric ammonium nitrate (CAN) as an initiator in the presence of nitric acid at 25 ± 1 °C. The extent of acrylamide grafting increased in the presence of the EA comonomer. The composition of the grafted chains (F_AAm = 0.52) was found to be constant during the feed molarity variation from 7.5 × 10^?2 to 60.0 × 10^?2 mol L^?1, whereas the composition of the grafted chains (F_AAm) was found to be dependent on feed composition (f_AAm) and reaction temperature. The effects of ceric(IV ) ion concentration, reaction time and temperature on the grafting parameters have been studied. The grafting parameters showed an increasing trend up to 6.0 × 10^?3 mol L^?1 concentration of CAN at a feed molarity of 30.0 × 10^?2 mol L^?1 and showed a decreasing trend on further increasing the concentration of CAN (>6.0 × 10^?3 mol L^?1) at a constant concentration of nitric acid (5.0 × 10^?2 mol L^?1). The composition of the grafted chains (F_AAm) was determined by IR spectroscopy and nitrogen content and the data obtained then used to determine the reactivity ratios of the acrylamide (r₁) and ethyl acrylate (r₂) comonomers by using a Mayo and Lewis plot. The reactivity ratios of acrylamide and ethyl acrylate were found to be r₁ = 0.54 and r₂ = 1.10, respectively, and hence the sequence lengths of acrylamide (m?M₁) and ethyl acrylate (m?M₂) in the grafted chains are arranged in an alternating form, as the product of the reactivity ratios of acrylamide and ethyl acrylate (r₁ × r₂) is less than unity. The rate of graft copolymerization of the comonomers onto cellulose was found to be dependant on the ‘squares’ of the concentrations of the comonomers and on the ‘square root’ of the concentration of ceric ammonium nitrate. The energy of activation (ΔE_a) of graft copolymerzation was found to be 5.57 kJ mol^?1 within the temperature range from 15 to 50 °C. On the basis of the results, suitable reaction steps have been proposed for the graft copolymerzation of acrylamide and ethyl acrylate comonomers from their mixtures. Copyright © 2005 Society of Chemical Industry     

球形纤维素珠体-AN-AM接枝共聚物的制备

以球形纤维素珠体为原料,丙烯腈(AN)和丙烯酰胺(AM)为单体,硝酸铈铵和过硫酸钾(KPS)为引发剂,制备纤维素珠体-AN-AM接枝共聚物,并通过正交单因素实验,研究了反应温度、引发剂用量、单体用量、反应时间等因素对接枝效果的影响。实验结果表明:当反应温度为60℃,引发剂硝酸铈铵用量为20%,KPS用量为15%(引发剂与单体AN的质量百分比),单体AN浓度为0.75 mol/L,AM浓度为0.28 mol/L,硝酸浓度为0.14 mol/L,反应时间为3 h时,接枝效果最好。此条件下,AN、AM与纤维素的接枝率可达259.4%,接枝效率可达49.40%。     

羧甲基甲壳素接枝甲基丙烯酸甲酯的制备及成膜性

通过高速搅拌,未使用乳化剂,制备了羧甲基甲壳素和甲基丙烯酸甲酯的接枝共聚物,避免了产物中引入乳化剂杂质。利用红外光谱对接枝共聚物进行了表征。考察了不同接枝率的产物在12种常见溶剂中的溶解性,结果表明,不同接枝率的接枝共聚物都有良好的水溶性,可以形成无色透明的膜,扩大了其实际应用价值。     

Synthesis,properties and degradation of polyisobutylene–polyester graft copolymers

The development of copolymers is a promising approach for combining the favorable properties of two polymers and obtaining new properties of the combination. In this work, graft copolymers of polyisobutylene (PIB ) and polycaprolactone or poly(d ,l ‐lactide) were synthesized and studied. Amine‐terminated polyesters were synthesized and were grafted onto an activated PIB backbone synthesized from butyl rubber, a copolymer of isobutylene and 2 mol% isoprene. The polyester content was tuned from 15 to 44 wt% by varying the molar mass of the polyester blocks and the number of molar equivalents used in the grafting reaction. The graft copolymers with higher polyester content underwent nanoscale phase separation, as demonstrated by differential scanning calorimetry and atomic force microscopy imaging. This was found to provide enhanced mechanical properties such as increased tensile strength and Young's modulus relative to the starting rubber or physical blends. Despite the significant polyester content of the graft copolymers and the susceptibility of the polyesters to degradation, the graft copolymers underwent negligible mass loss in 5 mol L^?1 NaOH over a period of eight weeks. These results suggest that polyesters can be incorporated into PIB to tune and enhance its properties, while maintaining high chemical stability. © 2016 Society of Chemical Industry     

Surface properties of block and graft polystyrene–polydimethylsiloxane copolymers

The surface compositions of a series of polystyrene‐b‐polydimethylsiloxane (PS‐b‐PDMS) and polystyrene‐g‐polydimethylsiloxane (PS‐g‐PDMS) copolymers were investigated using ATR‐FTIR and XPS technique. The results showed that enrichment of PDMS soft segments occurred on the surface of the block copolymers as well as on that of graft copolymers. And the magnitude order of the enrichment was as follows: PS‐b‐PDMS > PS‐g‐PDMS, which was attributed to the facilitating of the movement of the PDMS segments in PS‐b‐PDMS copolymer. Meanwhile, the solvent type and the contact medium had influence on the accumulation of PDMS on the surfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

均相制备纤维素/丙烯酰胺/甲基丙烯酸丁酯接枝共聚物的研究

以氢氧化钠/硫脲/尿素新型溶液溶解纤维素,在均相条件下以丙烯酰胺(AM)、甲基丙烯酸丁酯(BMA)为接枝单体,过硫酸铵为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,通过自由基聚合法制备出了纤维素/AM/BMA接枝共聚物。考察了聚合温度、时间以及(NH4)2S2O8、AM、BMA、MBA的用量对接枝效果的影响。利用红外光谱(FT-IR)、X射线衍射(XRD)和扫描电镜(SEM)对接枝产物进行了结构表征。实验结果表明,纤维素/AM/BMA接枝共聚物的最佳合成条件为:m(纤维素)∶m(AM)∶m(BMA)∶m[(NH4)2S2O8]∶m(MBA)=1∶4∶2∶0.05∶0.006,反应温度为65℃,反应时间为2h,在此条件下接枝率可达87%,接枝效率为36%。制备的纤维素/AM/BMA接枝共聚物的吸水倍率为583g/g。     

吸水性淀粉接枝共聚树脂

介绍了吸水性淀粉接枝共聚树脂的制备方法,主要特点,吸水机理及其在农业,医疗卫生,工业及环保中的应用。     

羧甲基纤维素接枝AM和DMC制备高吸水性树脂研究

采用水溶液聚合法,以(NH4)2S2O8-NaHSO3为引发剂、N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,单体丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)与羧甲基纤维素(CMC)接枝共聚,制得含有阳离子和非离子亲水基团的耐盐高吸水性树脂,研究了聚合反应条件对树脂吸水性能的影响.结果表明,在m(AM):m(DMC)=3:1、CMC加量为单体质量的4%～5%、引发剂占单体质量的0.3%～0.4%、交联剂占单体质量的0.5%、聚合温度为55～60℃、反应时间为3～4 h的优化反应条件下,所得树脂吸去离子水率为430 g·g-1,吸0.9%NaCl盐水率为86 g·g-1.     

Mechanical properties of conducting H‐type polysiloxane–polypyrrole graft copolymers and polytetrahydrofuran–polypyrrole block copolymers

The mechanical properties of block copolymers of polypyrrole and pyrrolyl‐ended azobis‐polytetrahydrofuran (TPPy) and graft copolymers of pyrrolyl‐ended H‐type polydimethylsiloxane (SPPy) were investigated and compared with those of polypyrrole (PPy). Conducting films were prepared electrochemically at a constant potential and doped with p‐toluene sulfonate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1663–1666, 2002     

Biosynthesis and characterization of bacteria cellulose–alginate film

A novel polysaccharide membrane containing alginate in bacterial cellulose matrix was synthesized by Acetobacter xylinum under static conditions using a culture medium supplementation with sodium alginate. By increasing alginate content, the bacterial cellulose–alginate (BCA) membrane was more hydrophilic and the film structure became denser with the smaller average pore size. Scanning electron microscope images displayed the deposits of alginate gel on the surfaces of the multilayer cellulose film. The declines in the tensile strength, the Young's modulus, and the elongation at break of the BCA membrane were dependent on the degree of alginate supplement. The BCA membrane showed higher water absorption capacity. The addition of alginate slightly affected the water vapor transmission rate but remarkably decreased the oxygen transmission rate of the membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Water‐soluble grafted polysaccharides containing sulfobetaine groups: Synthesis and characterization of graft copolymers of hydroxyethyl cellulose with 3‐dimethyl(methacryloyloxyethyl)ammonium propane sulfonate

New water‐soluble grafted polysaccharides containing sulfobetaine groups were synthesized by the grafting of the sulfobetaine‐type zwitterionic monomer 3‐dimethyl‐(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS) onto hydroxyethyl cellulose (HEC) in the presence of a ceric ammonium nitrate (CAN)/ethylenediaminetetraacetic acid (EDTA) initiation system. The effects of the concentrations of CAN, EDTA, DMAPS, and HEC, as well as the polymerization time and temperature, on the grafting reactions were investigated in terms of the grafting percentage (%GP) and grafting conversion (%GC) of the monomer. The %GP and %GC increased and then decreased with increasing concentrations of CAN, EDTA, and HEC. The %GP and %GC increased with increasing DMAPS concentration up to a certain value, beyond which the %GP did not significantly increase and the %GC decreased. The appropriate polymerization time and temperature were favorable for the grafting reactions. With infrared, thermogravimetric analysis, and viscosity measurements, the resulting grafted polysaccharides were characterized. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2755–2761, 2002; DOI 10.1002/app.10191     

Preparation,characterization, and behavior of cellulose–titanium(IV) oxide modified with organosilicone

Cellulose–titanium(IV) oxide modified with organosilicone (CTSN) was prepared by a reaction of cellulose powder with titanic chloride, followed by a reaction with 4‐aza‐6‐aminohexyl triethoxysilane, and was characterized by infrared spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis. An SEM image of titanium(IV) oxide‐coated cellulose and a Ti mapping image showed that titanium oxide was well dispersed on the cellulose surface. Titanium and silicon mapping images of CTSN, obtained with SEM, indicated that both oxides were uniformly dispersed on the cellulose surface. The atomic ratio of Ti to Si was obtained with X‐ray energy spectral composition analysis. The adsorption behavior of CTSN toward Hg(II), Cu(II), Pb(II), Fe(III), and Cr(III) ions in aqueous solutions was determined. The adsorption behavior of CTSN toward human serum protein was preliminarily examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 61–66, 2002; DOI 10.1002/app.10188