绢云母/聚丙烯酰胺/壳聚糖高吸水树脂的制备研究

以壳聚糖为基体,丙烯酰胺为接枝单体,利用接枝聚合法制备绢云母/聚丙烯酰胺/壳聚糖复合吸水树脂,研究单体与壳聚糖比例、交联剂、引发剂、添加剂等用量以及温度对吸水性能的影响,并用扫描电镜及红外光谱对吸水树脂进行表征。实验结果表明绢云母加入可以提高吸水树脂的耐盐性能。当温度为50℃、丙烯酰胺与壳聚糖的比例为20∶1、引发剂、绢云母以及交联剂用量分别占单体质量的2%、20%、0. 14%时,制备的吸水树脂具备最大的吸水倍率。     

超吸水性接枝共聚淀粉的制备工艺研究

以玉米淀粉为原料,丙烯酸为接枝单体,K_2S_2O_8-Na_2S_2O_3为引发剂,制备了丙烯酸接枝淀粉超强吸水剂。通过正交实验优化了接枝工艺,并以吸水倍率为指标,确定了最佳工艺条件:淀粉与丙烯酸质量比1:4,引发剂用量为淀粉质量的3.5%,交联剂用量为淀粉质量的0.8%,接枝温度为35℃,接枝时间为2h。在此条件下合成的丙烯酸接枝淀粉超强吸水剂对纯水的吸水倍率可达368%。     

超吸水性接枝共聚淀粉篚制备工艺研究

以玉米淀粉为原料,丙烯酸为接枝单体,K2S2O8-Na2S2O3为引发剂,制备了丙烯酸接枝淀粉超强吸水剂。通过正交实验优化了接枝工艺,并以吸水倍率为指标,确定了最佳工艺条件：淀粉与丙烯酸质量比1：4,引发剂用量为淀粉质量的3．5％,交联剂用量为淀粉质量的0．8％,接枝温度为35℃,接枝时间为2h。在此条件下合成的丙烯酸接枝淀粉超强吸水剂对纯水的吸水倍率可达368％。     

交联型吸水膨胀天然橡胶的吸水性能

以天然胶乳为原料,丙烯酰胺为吸水单体,通过接枝共聚反应制得吸水膨胀天然橡胶(WSNR)。分别以甲醛为单体交联剂,硫磺为天然橡胶交联剂,经过接枝共聚反应制备单体交联型吸水膨胀天然橡胶(WSNR-c)和橡胶硫化交联型吸水膨胀天然橡胶(WSNR-v)。研究了不同交联方式对吸水膨胀橡胶吸水倍率、重复吸水能力和弹性模量的影响,并对吸水膨胀天然橡胶中水的状态、热失重过程和微观形貌进行分析。结果表明：吸水膨胀天然橡胶的吸水倍率、重复吸水恢复率和储能模量随着吸水单体和天然橡胶交联程度的提高而降低;交联处理使吸水膨胀天然橡胶吸束缚水的能力减弱,失水稳定性降低;吸水膨胀天然橡胶经交联处理后体系网络结构致密,孔洞减少。     

丙烯酰胺/甲基丙烯酸丁酯改性纤维素的研究

以纤维素为基体,丙烯酰胺(AM)、甲基丙烯酸丁酯(BMA)为接枝单体,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,聚乙烯吡咯烷酮为分散剂,通过悬浮接枝聚合法制备出了纤维素基吸水吸油材料;考察了单体用量、引发剂用量、反应时间、反应温度及交联剂用量等因素对接枝聚合物的吸水、吸油性能的影响。结果表明:在单体与纤维素的质量比为3.0∶1.0,AM∶BMA的质量比为2.0∶1.0,相对于单体,引发剂质量分数为6.0%,交联剂质量分数为0.5%,分散剂质量分数为0.5%,反应温度为70℃,反应时间为4 h的条件下,得到纤维素-AM-BMA接枝共聚物,其吸油倍率为11.55 g/g,吸水倍率为23.51 g/g,聚合度为534.6。     

玉米秆制取吸水树脂的研究

以玉米秆为原料制取羧甲基纤维素钠,与丙烯酸接枝共聚制备吸水树脂.讨论了单体配比、丙烯酸中和度、交联剂用量及引发剂用量等因素对吸水性能的影响.实验发现,在丙烯酸单体与玉米秆质量比为8∶1、丙烯酸中和度为70%、交联剂N,N-亚甲基双丙烯酰胺为丙烯酸单体质量的0.24%、引发剂过硫酸钾为丙烯酸单体质量的3.5%、反应温度为60℃的条件下,所得树脂吸水倍率最高可达68 g/g.     

蛋膜改性接枝丙烯酸高吸水树脂的制备及性能研究

以废弃蛋膜和丙烯酸为主要原料,以N,N'-亚甲基双丙烯酸胺为交联剂,过硫酸钾为引发剂,采用水溶液聚合法制备了改性蛋膜-聚丙烯酸高吸水性树脂。考察了聚合温度、引发剂和交联剂的用量以及改性蛋膜用量等各因素对树脂吸水倍率的影响。结果表明,聚合温度70℃,改性蛋膜用量为单体质量的10%,丙烯酸中和度为70%,引发剂用量为单体质量的0.1%,交联剂用量为单体质量的0.12%,树脂的吸水倍率可达667 g/g,在0.9%的NaCl溶液中吸盐水倍率达到106 g/g,其吸水速率较快。IR初步表明了蛋膜与丙烯酸的接枝聚合作用。     

纸浆纤维素基高吸水材料的制备及性能研究

以纸浆纤维素为骨架接枝单体丙烯酸和丙烯酰胺,在无N2保护下利用微波辅助引发,考察了纸浆纤维/丙烯酸/丙烯酰胺质量比、单体浓度、引发剂用量和交联剂用量对材料吸水性能的影响,通过FTIR、XRD对所得吸水材料进行了结构表征。所得吸水材料为白色透明薄膜状,易于加工成型,吸水后柔软度及强度很高,纸浆质量分数为25%时吸去离子水倍率为471g/g,吸0.9%NaCl水溶液倍率为135g/g,吸雨水倍率为89g/g,并可反复使用,具有一定的应用价值。     

麦秸秆纤维素与丙烯酸接枝共聚制备耐盐性吸水树脂的研究

应用小麦秸秆与丙烯酸接枝共聚制备了耐盐性吸水树脂,进行了结构表征,研究了单体配比、丙烯酸中和度、引发剂和交联剂用量以及反应温度对吸盐水倍率的影响。研究发现,接枝共聚的适宜条件为:丙烯酸单体与麦秸秆质量比为8∶1,丙烯酸中和度为70%,引发剂过硫酸钾-硫代硫酸钠的用量为单体的3.5%,交联剂N,N-亚甲基双丙烯酰胺用量为单体质量的0.24%,反应温度为70℃。在此条件下制备的树脂吸盐水倍率最高,吸盐水(CNaC l=0.9%)可达68 g/g,可应用于医疗卫生等方面。     

淀粉接枝丙烯酰胺与丙烯酸的实验研究

在氮气保护下，以N，N’-亚甲基双丙烯酰胺为交联剂，过硫酸铵和亚硫酸钠作为引发剂，淀粉与丙烯酰胺、丙烯酸接枝共聚。经干燥后制备吸去离子水迭700倍的吸水性树脂。探讨了反应时间、交联剂用量、引发剂用量、单体中和度、反应温度、淀粉用量、干燥温度对吸水倍率的影响。     

Amphiphilic particulate phase semi-interpenetrating polymer networks based on recycled rubber matrix

The goal of this study is to enable the utilization of recycled rubber particles in aqueous media by producing amphiphilic particulate phase semi-interpenetrating polymer networks (PPSIPNs). Rubber granulates obtained from post-consumer rubber items were pulverized into fine particles using a solid state shear extrusion (SSSE) process. Reaction mixtures composed of toluene, acrylic acid (AA) monomer and azobisisobutyronitrile (AIBN) as an oil-soluble initiator were prepared and used to impregnate the produced rubber particles. Toluene was added as a co-swelling agent to induce more swelling of the rubber particles and, consequently, enhancement in the absorption of AA in the rubber network. The swollen particles were introduced into a micro-domain suspension polymerization reactor where the ionic strength of the aqueous phase was sufficient to prevent desorption of AA from the particles during the reaction. This resulted in formation and interpenetration of hydrophilic poly(acrylic acid) in the intermolecular structure of hydrophobic rubber network. The resulting composite particles are water dispersible and suitable for use in a variety of aqueous applications such as, additives to waterborne emulsions and vehicles for wastewater treatment.     

Effects of fillers on mechanical properties of a water‐swellable rubber

The mechanical properties of the water‐swellable rubber prepared by blending polychloroprene with precipitated silica, crosslinked sodium polyacrylate, polyethylene oxide, and vulcanizing agents—such as stress at break, strain at break, modulus, energy at break, and hardness—were studied before and after swelling with water. The results showed that the addition of the reinforcing filler (precipitated silica) increased the mechanical properties, while adding crosslinked sodium polyacrylate decreased the mechanical properties, although it could improve water‐absorbent properties of the water‐swellable rubber. If some polyethylene oxide was included in the rubber formulation, the water‐absorbent properties and the mechanical properties of the rubber both increased; but, with the increase of more polyethylene oxide, the mechanical properties decreased. Wide‐angle X‐ray diffracting analysis was conducted to study the crystalline behavior of the rubber, which showed that the crystallinity of the vulcanized polychloroprene increased first and then decreased with an increase in the amount of polyethylene oxide. The crosslink density of the rubber was calculated by the Flory–Rehner equation. The mechanical strength of the rubber significantly decreased after swelling with water, compared with that before swelling with water. The morphology of blends was shown by scanning electron microscopy graphs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 577–584, 1999     

Multiporous microstructure for enhancing the water absorption and swelling rate in poly(sodium acrylic acid) superabsorbent hydrogels based on a novel physical and chemical composite foaming system

In this article, we report a novel physical and chemical composite foaming system, which was used to successfully prepare high‐performance and low‐cost composite superabsorbent [poly(sodium acrylic acid) (PAA–Na)] hydrogels based on acrylic acid by free‐radical polymerization in a water bath under a nitrogen atmosphere without the use of any organic solvents. The prepared hydrogels showed superabsorbent properties, high water‐absorption abilities and swelling rates, a lighter packing density, and a multiporous microstructure. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that the sodium dodecyl sulfate surfactant, sodium bicarbonate chemical foaming agent, and 1,1,2‐trifluorotrichloroethane physical foaming agent were evenly distributed and grafted onto the PAA–Na matrix. Water‐absorption, swelling rate, and packing density testing confirmed that the superabsorbent had a high water‐absorption ability and swelling rate and a lighter packing density. Furthermore, we investigated the effects of different foaming agents, including chemical and physical foaming agents, on the swelling and water‐retention capabilities of the superabsorbent hydrogels (SAHs).The results show that the combination of these foaming agents significantly improved the water‐absorbing capacity. With the help of these foaming agents, we obtained PAA–Na hydrogels without any organic solvents for posttreatment or special porogens; this is an environmentally beneficial way to prepare SAHs for hygiene and biomedical products. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44149.     

三氯化铝交联淀粉高吸水性树脂的合成及性能

以马铃薯淀粉为原料,丙烯酸为接枝单体,过硫酸钾为引发剂,三氯化铝为交联剂,合成了淀粉接枝丙烯酸高吸水性树脂,并对产物进行性能测试和红外、紫外可见光谱的结构表征。考察了影响产物吸水性能的5个合成条件,在反应温度65℃,3 mLw(K2S2O8)=1%水溶液,2 mLw(AlCl3)=1%水溶液,m(淀粉)∶m(丙烯酸)=1∶6,单体中和度70%时,树脂达到最高的吸去离子水倍数1 440 g/g。产物粉末2 min可达到饱和吸水率的50%,凝胶能有效延长水分蒸发时间,吸自来水率达到560 g/g,具有良好的工农业和市场应用前景。     

New smart carrageenan‐based superabsorbent hydrogel hybrid: Investigation of swelling rate and environmental responsiveness

Synthesis of novel natural‐based superabsorbents with improved properties is of prime importance in many applications. In this article we report an efficient synthesis of new polysaccharide‐based superabsorbent hybrid composing carrageenan, acrylic acid, sodium acrylate, and 2‐hydroxyethyl acrylate through homogenous solution polymerization process. Infrared spectroscopy and thermogravimetric analysis (TGA) were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM). To deeper studies on the structure‐property relation in SAP hydrogels, three hydrogels with different acrylic acid/2‐hydroxyethyl acrylate (AA/HEA) weight ratios were synthesized and swelling capacity in various media was assessed. The hydrogel hybrid was also tested to be swollen and deswollen alternatively in 0.01 and 0.1 M sodium chloride solution. Moreover, the swelling‐deswelling capability of the hydrogel in alternatively changed methanol‐water mixtures was studied. Additionally, the swelling kinetics of the synthesized hydrogels were examined. The absorbency under load (AUL) of hydrogel was also investigated by using an AUL tester at various applied pressures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A study on morphology and physical properties of natural–acrylic rubber blends

Morphology and physical properties of natural–acrylic rubber blends were investigated as a function of blend compositions and mixing methods. In the first method, the masticated natural rubber was cross‐blended with the acrylic rubber for 15 min, followed by a sequential addition of vulcanizing chemicals (ZnO, stearic acid, MBT, sodium stearate, and sulfur), and the mixing was terminated within 15 min. In the second method, the masticated natural rubber was premixed with its relevant vulcanizing chemicals (excepting the sulfur) for 7 min, followed by blending it with the acrylic rubber and sodium stearate for 20 min. Finally, the sulfur was added and the mixing was continued for further 3 min before termination. The resulting blends were vulcanized to their optimum cure time in a compression mold. The rubber sheet was cut into a dumbbell‐shaped specimen, and tensile properties were determined at a cross‐head speed of 500 mm/min. The morphology of the blends was examined with scanning electron microscopy (SEM). The SEM specimen was prepared by cryo‐fracturing, followed by staining with OsO₄. It was found that all of the rubber blends were immiscible, as shown by there being two separated phases in the SEM micrographs. The result was in a good agreement with that from a thermal analysis (using a differential scanning calorimeter), which showed two glass transition temperatures. Morphology of the rubber blends changed from a cocontinuous morphology to a dispersed particle morphology as the natural rubber content was increased from 20% to 80% by weight. Increasing the natural rubber content enhanced tensile properties of the rubber blends at the expense of their oil and heat resistance. Most of these properties being examined seemed to be unaffected by the mixing method, with the exception of the retention of tensile strain after aging. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1532–1539, 2002     

Study of water sorption in rubbers by acoustic microscopy

Acoustic microscopy has been used to examine changes during water swelling at the surface of a rubber previously treated with an acrylic monomer. Surface modification was carried out with acrylic acid either in aqueous solution or in the vapour phase, and a photografting reaction was achieved with an aqueous solution of acrylic acid in the presence of a photo‐initiator. Water sorption induces modifications of the mechanical properties, transforming a rigid polymer into a soft material. Therefore, the acoustic impedance of the material decreases during the swelling process and the evolution of acoustic reflection coefficient is followed. The potential of ultrasonic measurements as an in situ and non‐destructive dynamic analysis technique is demonstrated. Mapping of grafted and ungrafted areas on a rubber surface is obtained with acoustic microscopy. © 2000 Society of Chemical Industry     

Electron-microscopic procedure for acrylic rubber

The electron-microscopic visualization of acrylic rubber dispersed in a heterogeneous structural resin composition consisting of a rubber-modified two-phase plastic comprising essentially a butyl acrylate rubber phase and an acrylonitrile–styrene copolymer phase, respectively, has been accomplished. This procedure consists of the following: The molded resin specimen is treated with hydrazine hydrate solution to produce the acrylic acid hydrazides. Allow the treated specimen to soak in osmium tetroxide solution. The acrylic rubber may be indirectly fixed and stained. Some micrographs of ultrathin sections of two or three resin compositions, cut by an ultramicrotome, are presented.     

橡籽油的酸催化水解工艺研究

以橡籽油为原料进行常压一次酸催化水解反应。研究了反应温度、反应时间、催化剂用量、油水比和乳化剂用量对水解反应的影响,得出橡籽油水解的最优条件:反应温度为95℃,反应时间为9 h,催化剂浓硫酸用量为10%,油水比为1∶2,乳化剂十二烷基磺酸钠用量为1%,此时橡籽油的水解产物酸值为189.41mg KOH/g,水解率为94.71%。     

淀粉基高吸水性树脂的合成与性能研究

以马铃薯淀粉和丙烯酸(AA)为原料,过硫酸钾(K2S2O8)为引发剂,三氯化铝(AlCl3)为交联剂,采用以水为溶剂的溶液聚合法制备淀粉基高吸水性树脂(SAP)。确定合理的反应时间,评价树脂的吸水速率、反复吸水性及保水性能。结果表明,在ω(K2S2O8)=0.15%,ω(AlCl3)=0.10%,m(AA)∶m(starch)=6∶1,丙烯酸中和度70%,60℃的条件下,反应80 min制备的树脂吸蒸馏水率为1 235 g/g,吸质量分数为0.9%NaCl溶液率101 g/g,且吸水速率较快,SAP的重复吸水性能和保水性能较好。FTIR分析证实树脂为淀粉与丙烯酸(钠)的接枝共聚物,SAP的XRD衍射峰呈弥散衍射特征,TG和DTA分析说明SAP的热稳定性良好。