高吸水性树脂

高吸水性树脂,可以吸收其本身重量的几百倍水。将水溶性高分子如羧甲基纤维素、聚丙烯酸钠盐或聚乙烯醇进行轻微的交联可以得到。由于其高吸水性、在压力下的高保水性和高增稠性,被广泛应用于纸尿布、生理巾、土壤保水剂、工业脱水剂、增稠剂等。     

高吸水性枝脂研究进展

介绍了高吸水性树脂的结构,性能及其表征,结合经典理论与最新研究从热力学和动力学角度阐述其吸水机理,着重分析合成条件,组份和方法对高吸水性树脂性能的影响机制,简略地介绍了高吸水性树脂三十年来的发展及广阔的应用领域,并预测其研究与开发前景。     

高吸水性树脂研究进展

介绍了高吸水性树脂的结构、性能及其表征,结合经典理论与最新研究从热力学和动力学角度阐述其吸水机理,着重分析合成条件,组份和方法对高吸水性树脂性能的影响机制,简略地介绍了高吸水性树脂三十年来的发展及广阔的应用领域,并预测其研究与开发前景     

高吸水性树脂

综述了国内高吸水性树脂的研究进展,其中包括高吸水性树脂的制备方法、类型、影响其吸水性能的因素以及功能与应用。     

高吸水性树脂

用热力学理论和相转变理论阐明了高吸水性树脂的吸水机理。解释了高分子链上的电荷密度、外界溶液离子强度以及交联度对吸水倍数的影响，并指出了影响吸水速率的因素。介绍了淀粉类、纤维素类、共聚合类、复合类以及可生物降解类高吸水性树脂近30年来的研究状况以及存在的问题，简要介绍了高吸水性树脂的应用。     

高吸水性树脂的吸水机理

高吸水性树脂是三度空间网络聚合物，是高分子电介质。在高分子网络链上嵌有可电离的离子对，遇水形成离子网络。该树脂能吸收自身重量几百倍至几千倍的水，且保水性好，即使在压力下，水也不从中溢出。其吸水机理可用Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ热力学公式来解释。     

生物炭复合高吸水性树脂的尿素负载性能研究

以丙烯酸(AA)、丙烯酰胺(AM)和生物炭为原料,采用水溶液聚合法制备了生物炭复合高吸水性树脂(BC-SA),并研究了其尿素负载性能。通过正交试验和单因素实验,以尿素负载量为考察对象,得到最优合成工艺条件:生物炭质量分数5%,引发剂和交联剂质量均为聚合单体质量的0. 3%,中和度65%,反应温度65℃,该条件下制备的BC-SA尿素负载量可达77. 8%。利用傅里叶红外光谱(FT-IR)和热重(TG)分析对BCSA的结构及热稳定性进行了表征,结果表明,生物炭与AA、AM之间发生了接枝共聚反应;生物炭的加入使复合树脂的热稳定性有所提高。     

高吸水性树脂的合成和应用

本文综述了近年来高吸水性树脂的研究进展,主要包括3个方面:(1)高吸水性树脂的制备;(2)高吸水性树脂的结构及性能表征;(3)高吸水性树脂的应用开发。     

高吸水性树脂聚丙烯酸钠盐制备工艺研究

研究他聚俩烯酸钠在溶液聚合中，引发剂、交联剂、丙烯酸中和度、单体浓度和反应温度对树脂吸水性的影响，从中获得最佳合成工艺，制得树脂性能为吸去离子水１４００ｇ／ｇ，吸０。９％ＮａＣｌ溶液１５０ｇ／ｇ，吸水速率快，保水性较好。     

Nonwoven Releasing Propolis as a Potential New Wound Healing Method—A Review

Wound healing poses a serious therapeutic problem. Methods which accelerate tissue regeneration and minimize or eliminate complications are constantly being sought. This paper is aimed at evaluation of the potential use of biodegradable polymer nonwovens releasing propolis as wound healing dressings, based on the literature data. Propolis is honeybee product with antioxidant, antibacterial, antifungal, anticancer, anti-inflammatory, analgesic, and regenerative properties. Controlled release of this substance throughout the healing should promote healing process, reduce the risk of wound infection, and improve aesthetic effect. The use of biodegradable aliphatic polyesters and polyester carbonates as a propolis carrier eliminates the problem of local drug administration and dressing changes. Well-known degradation processes and kinetics of the active substance release allows the selection of the material composition appropriate to the therapy. The electrospinning method allows the production of nonwovens that protect the wound against mechanical damage. Moreover, this processing technique enables adjusting product properties by modifying the production parameters. It can be concluded that biodegradable polymer dressings, releasing a propolis, may find potential application in the treatment of complicated wounds, as they may increase the effectiveness of treatment, as well as improve the patient’s life quality.     

Hydrophobic Silica Aerogels Strengthened with Nonwoven Fibers

Hydrophobic silica aerogels were prepared via a sol‐gel process by surface modification at ambient pressure. Nonwoven fibers were distributed inside the silica aerogels as a composite to act as a supporting skeleton which increased the mechanical property of the silica aerogels. The morphology and pore structure of the composites were characterized by scanning electron microscopy (SEM) and N₂ adsorption analyzer. The contact angle and the adsorption capacities of the composites were also determined. The results show that silica aerogels dispersed uniformly and maintained high porosity in the aerogel‐fiber composites. They have excellent hydrophobic properties and are excellent adsorptive materials.     

生物降解材料

本文介绍了生物降解材料的含义、作用机理、影响微生物降解的因素、以及生物降解材料的应用,并列举了几种主要的可生物降解的材料。     

可生物降解聚合物的现状及生物降解性研究

综述了可生物降解聚合物的现状及发展、影响生物降解性的因素和生物降解性的评价方法。     

Biomedical Investigations of Biodegradable PHAs

This work is a review of the results of biomedical studies of polymer devices (films, fibers, microparticles, 3D implants) made from resorbable PHAs synthesized by the bacterium Wautersia (Ralstonia) eutropha B5786, using the technology developed at the Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences. Two types of PHAs – polyhydroxybutyrate (PHB) and a hydroxybutyrate/hydroxyvalerate copolymer (PHB/PHV) – have been proven to be biocompatible in vitro in cultures of fibroblasts, endothelial cells, hepatocytes, and osteoblasts, and in short- and long-duration experiments on animals. Polymer films and membranes have been found to be usable as scaffolds for functioning cells and monofilament suture fibers – for stitching muscular-fascial wounds and in abdominal surgery. Ectopic bone formation assay and experiments with the model of segmental osteotomy showed that 3D PHB and PHB/HA implants can be used for reparative osteogenesis. The paper reports beneficial results of using polymers to repair bone defects in oral surgery.     

An Investigation into Fiber Dispersion Behavior in Water with Reference to Wet-Lay Nonwoven Technology

This article reports on fiber dispersion behavior in water with reference to wet-lay nonwoven technology. The effects of fiber material characteristics and dispersion process conditions on the quality of the nonwoven webs were examined. The webs were characterized for their area-based uniformity by means of an imaging system in conjunction with quadrat analysis. It was found that the area occupied by the fibers in the webs followed the lognormal probability distribution and the angular orientation of the fibers in the webs followed the bimodal distribution. The web prepared by using scoured fibers was almost equally uniform as compared to the web prepared by using bleached fibers. The web made up of shorter and coarser fibers was more uniform than that made up of longer and finer fibers. The higher concentration of cationic surfactant resulted in more uniform webs. It was observed that the webs prepared at optimum stirring rate and dispersion time were found to possess the highest uniformity.     

水驻极熔喷非织造材料的制备与性能研究

口罩的核心功能层是熔喷非织造材料,为了满足高效低阻要求,需要对其进行电晕驻极和水驻极处理,但有关驻极机理方面的研究却鲜见报道,特别是水驻极.本文对比测试了电晕驻极和水驻极熔喷非织造材料的过滤效率和表面电荷分布,模拟了水驻极实验,并对水驻极机理进行了探索.结果 发现,相对于电晕驻极,水驻极能显著提高熔喷非织造材料的过滤效...     

Biodegradable compositions by reactive processing of aliphatic polyester/polysaccharide blends

Commercially available biodegradable aliphatic polyesters, i.e., high molecular weight poly(ϵ-caprolactone) (PCL) and polylactide (PLA), were melt blended with a well-known natural and biodegradable polysaccharide: starch either as corn starch granules or as thermoplastic corn starch after plasticization with glycerol. Conventional melt blending yielded compositions with poor mechanical performances as a result of lack of interfacial adhesion between the rather hydrophobic polyester matrix and the highly hydrophilic and moisture sensitive starch phase. Interface compatibilization was achieved via two different strategies depending on the nature of the polyester chains. In case of PLA/starch compositions, PLA chains were grafted with maleic anhydride through a free radical reaction conducted by reactive extrusion. The maleic anhydride-grafted PLA chains (MAG-PLA) allowed for reinforcing the interfacial adhesion with granular starch as attested by TEM of cryofracture surface. As far as PCL/starch blends were concerned, the compatibilization was achieved via the interfacial localization of amphiphilic graft copolymers formed by grafting of PCL chains onto a polysaccharide backbone such as dextran. The PCL-grafted polysaccharide copolymers were synthesized by controlled ring-opening polymerization of ϵ-caprolactone proceeding via a coordination-insertion mechanism. These compatibilized PCL/starch compositions displayed much improved mechanical properties as determined by tensile testing as well as a much more rapid biodegradation as measured by composting testing.     

高温高压水中干酪根热解的拉曼光谱原位研究

利用对顶砧压腔装置,以金刚石作为顶砧,通过观测和采用拉曼光谱对干酪根在高温高压水中热解的具体过程进行了原位研究.由于金刚石顶砧只在约1 332 cm-1波数出现一个很强很尖锐的峰,因此用于压 标的石英、介质水以及样品干酪根的拉曼峰都未受影响.测试了在450℃和850 MPa条件下干酪根变化的拉 曼峰.随着温度和压力的增加,干酪根在1 600 cm-1波数附近由于芳香环振动引起拉曼峰的最大峰位置 (vmax)和半高宽(FWHM)存在转折变化.在干酪根热解之前,其芳香环结构和无序结构之间的缺陷向有序化变化.而对于干酪根的热解过程,先是热解为液相碳氢化合物,随后进一步热解为更小分子的成分,如 CH4.干酪根的热解过程与压力密切相关,增加压力对热解存在抑制作用.     

Biodegradable Poly(3-hydroxybutyrate) Nanocomposite

This work seeks bringing a technological and social contribution by searching blends and composites of poly(3-hydroxybutyrate) (PHB) and polyethylene widely used in packaging films, and colloidal silica. The mixtures were prepared by extrusion using a single-screw extruder and were analyzed regarding their thermal and mechanical properties and morphology. The results have shown PHB toughness in the studied compositions, which elongation at break was in the range 5–80% compared to 2% for neat PHB. The small amount (0.2 to 0.4%) of added silica seemed to increase in 20% the tensile strength. The thermal degradation by thermogravimetry from room temperature to 800 °C revealed a mixed behavior for the composites between PHB and polyethylene.