可生物降解高分子材料的研究与进展

高分子材料难以自然降解,会造成环境污染。可生物降解高分子材料在其使用寿命后,可以自行降解,是未来高分子材料发展的重要方向之一。简要介绍了生物降解高分子材料及其分类,探讨了可生物降解材料的降解机理、影响材料生物降解的因素和生物降解材料的制备方法、评价方法、研究与应用概况,并指出了可生物降解高分子材料未来发展的方向。     

生物可降解高分子材料在避孕领域中的应用进展

一些生物可降解高分子材料由于具有良好的生物相容性,并且它们的降解产物对机体毒副作用小,因而具备了应用到人体内的条件.在现代药荆学中,生物可降解高分子材料的应用也越来越受到重视.采用不同方法制备的生物可降解高分子为载体的避孕剂,栽体材料在体内能够降解,并且降解产物可以被排出体外.综述生物可降解高分子材料在避孕领域的应用情况.     

可降解高分子材料研究进展及在快递绿色包装领域的应用

可降解高分子材料是一种能被微生物和光降解,降解产物对环境无污染的新型材料,在农业渔业、医疗器械、汽车零部件、食品与快递包装等领域得到广泛应用。该文介绍了可降解高分子材料的种类和应用,结合目前垃圾围城的现状和全民垃圾分类"新时尚",针对快递行业低碳发展现状,概括了新型降解材料在快递绿色包装的实际应用,最后对可降解高分子材料未来发展进行了展望。     

微波在合成天然有机高分子改性絮凝剂中的应用进展

微波辐射技术具有能耗低、反应速率快且有助于改善产品品质的特点,为合成天然有机高分子改性絮凝剂提供了新的思路。简述了微波合成的发展和机理,介绍了近年来微波辐射技术在合成天然有机高分子改性絮凝剂中的应用,展望了微波促进天然有机高分子改性的发展方向。     

导电高分子材料研究进展

综述导电高分子材料的发展及应用。介绍导电高分子材料的分类,复合型及结构型导电高分子材料的导电机理,以及它们在膜分离技术、微波焊接、防腐、电致变色器件等方面的应用。并指出了导电高分子材料目前的研究趋势。     

微波在化学反应中的应用

针对微波加热在纳米材料制备、有机化学反应、高分子化学反应以及新型炭(碳)材料的制备和加工,特别是在无机纳米粒子改性、聚合物微球合成中的应用进展进行了综述。     

微波诱导降解有机废水的研究进展

概括了微波的作用原理,综述了微波/吸波剂、微波/氧化剂、微波/催化剂/氧化剂联合作用在降解有机废水方面的反应条件、降解效率和原理优势,分析了微波诱导降解在处理有机废水技术中存在的问题,展望了今后的发展方向,为微波诱导降解技术的研究与应用提供参考。     

环境降解塑料的研究开发进展

介绍了环境降解塑料的降解机理及其分类。综述了光降解高分子材料、生物降解高分子材料的种类、制备方法、性能及其应用。指出了环境降解高分子材料存在的问题及发展方向。通过比较认为光降解高分子材料技术比较成熟，完全生物降解高分子材料发展前景看好，并对今后的发展提出了建议。     

降解性高分子材料的研究开发进展

综述了生物降解高分子材料,光降解高分子材料和光－生物降解高分子材料的种类、制备方法、性能及其应用,指出了降解高分子材料存在的问题方向,通过比较认为光降解高分子材料技术比较成就,完全生物降解高分子材料和光－生物降解高分子材料发展前景看好,并对今后的发展提出了建议。     

木质素化学降解及其在聚合物材料中应用的研究进展

木质素是自然界储量丰富的可再生天然酚类高分子，可替代传统化石资源应用于聚合物材料合成。木质素分子结构中的大分子刚性骨架可赋予材料独特的力学性能和热稳定性。但木质素化学组成和分子结构复杂、反应活性低，限制了在聚合物材料领域的应用。化学降解是一种高效、高选择性且应用广泛的降解方法，经化学降解处理得到的木质素低聚物具有活性官能团多、反应活性高、溶解性好等优点，有利于拓展木质素在聚合物材料领域的高附加值应用。重点综述了近年来国内外有关木质素化学降解及其降解产物应用于聚合物材料的研究进展。     

微波在聚合物科学中的应用

综述了聚合物科学中微波应用的研究进展,讨论了微波在聚合物合成中的研究概况。也介绍了聚合物微波加工的原理及对材料结构与性能的影响,一方面微波在树脂固化中得到广泛的应用;另一方面微波在橡胶硫化中也取得了较大的成功。另外也介绍了微波在聚合物改性方面的应用。最后指出目前存在的一些问题。     

硫酸铁改性活性炭催化微波降解甲基橙的研究

在硫酸铁改性活性炭存在下,微波照射能使溶液中的甲基橙迅速降解。对总体积25ml,浓度500mg／L的甲基橙溶液,改性活性炭加入量2．0g／L微波辐射3．0分钟,降解率达76．60％。适当提高活性炭加入量,如3． 0g／L,同样辐射时间可达95．40％。在同样条件下采用未改性活性炭时,其降解率分别为69．53％和90．97％。采用紫外-可见光谱和离子色谱技术探讨了微波辐射时间、甲基橙初始浓度、活性炭用量、改性硫酸铁浓度和溶液酸度对降解甲基橙的影响。     

溶胶-凝胶-微波法制备银掺杂TiO_2光催化剂及其光催化性能

用硝酸银和钛酸正丁酯为原料,采用溶胶-凝胶-微波辐射干燥法合成银掺杂TiO_2光催化剂TiO_2-Ag。为了提高催化剂的光催化活性和降解有机污染物的速率,用微波辅助Ti O2-Ag光催化剂降解有机污染物。通过扫描电子显微镜、红外光谱法、紫外可见光谱法和荧光光谱法对TiO_2-Ag催化剂进行测试和表征。以甲基橙为有机污染物,分别在太阳光照射和微波、紫外、紫外-微波条件下降解甲基橙以考察催化剂的光催化活性。结果表明,TiO_2-Ag光催化剂最佳制备条件为:银掺杂量n(Ag+)∶n(Ti~(4+))=0.003,离子液体用量3.0 m L,微波干燥功率210 W,微波干燥时间20 min,焙烧温度650℃,焙烧时间3 h,此条件下制备的TiO_2-Ag光催化剂在太阳光照射4 h下,紫外光照、微波辐射和紫外光照-微波辐射分别辐射55 min后,甲基橙降解率分别为98.70%、98.79%和99.05%。     

Prospects for modification of para-aramid fibres with metal complex salts in conditions of microwave exposure

The important possibility of conducting sol-gel synthesis of oxide systems on the surface of para-aramid fibres under the effect of microwave radiation was demonstrated. Selection and control of the basic process parameters (duration and intensity of exposure to electromagnetic radiation, concentration of salt and carbamide) allow regulating the effectiveness of interaction of the reaction system with the microwave field and eliminating degradation of the polymer, i.e., preserving its basicphysicomechanical indexes. __________ Translated from Khimicheskie Volokna, No. 3, pp. 18–20, May–June, 2007.     

微波再生技术在废水处理中的应用

微波技术作为一种新型物化处理手段已广泛应用于环境领域,微波处理溶液中的污染物有两种方式,一种是直接用微波辐射含有污染物的溶液,采用微波场助化学反应的方法加速污染物的降解;另一种是先将污染物吸附到活性炭或其它吸附剂上,然后置于微波场中辐射,使污染物降解,也即微波再生技术在水处理中的应用。探讨了物质在微波辐射中发生的变化,再生的机理,并对目前在废水处理领域中,微波再生技术的应用,特别是微波再生活性炭技术的应用进行了全面的总结和概括。     

Basic ideas of microwave processing of polymers

The objective of this effort has been to investigate the relationship between polymer structure and microwave absorptivity. Dielectric loss factor, ε″, loss tangent, tan δ, and oscillator strength, (ε_S ?- ε_∞), were used to evaluate potential material processability under applied microwave radiation. Numerous polymeric materials varying in chemical and physical structures were irradiated in a low power (≤ 100W) electric field at 2.45 GHz. Electromagnetic radiation was applied as either traveling or resonant wave modes in cylindrical and rectangular waveguides. In general, heatability was found to be a direct function of the dielectric loss dispersion dependence on temperature and frequency. The dielectric loss factor obtained at low frequency measurements was found to be directly proportional to the heatability of polymers. A WLF plot was used to predict the shift of dielectric loss maxima into or out of the microwave frequency range.     

Evolution to similarity solutions for polymerization and depolymerization with microwave radiation

The kinetics of polymerization and depolymerization are critical in understanding the stability and characterization of polymers. The kinetics of simultaneous polymerization and degradation of poly(methyl methacrylate) have been investigated by varying the initiator concentration and monomer concentration under the influence of microwave energy. Microwave radiation initially polymerizes the monomer, then degrades the resulting polymer and the polymer attains an equilibrium molecular weight distribution with a polydispersity of two. To understand more fully the kinetics, the molecular weight distribution (MWD) is represented as a gamma distribution; the random degradation rate coefficient is assumed to vary linearly with molecular weight and the polymerization rate coefficient is assumed to be independent of molecular weight. The change of the MWD with time is studied by continuous distribution kinetics; the solutions obtained depict the change of the average molecular weight, polydispersity and the gamma distribution parameters with time. Experimental data indicate that reaction rates are enhanced by microwave radiation and the MWD approaches a similarity solution within 10 min for all the investigated cases. The model satisfactorily predicts the change of the MWD with time. © 2001 Society of Chemical Industry     

Novel synthesis of polyimides of the third‐order optical nonlinearities by microwave assistance

The third‐order optical nonlinearities and time responses of three new polymeric materials, which were prepared by polymerization of benzoguanamine (BGA) and pyromellitic dianhydride (PMDA), m,m′‐diaminobenzophenone (m,m′‐DABP) and PMDA, BGA, and 2,4‐tolylenediisocyanate (TDI) under microwave radiation, were measured by a picosecond forward three‐dimensional degenerate four‐wave mixing technique. The experimental results showed that nonresonant optical nonlinearity [χ⁽³⁾] of the three polymers is larger by microwave than by heating and that third‐order optical nonlinearities were not only affected by the length of polymer chain, but also by the polymer chain structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1739–1747, 2003     

微波合成N-苄基-4-哌啶酮的研究

以苄胺和丙烯酸甲酯为起始原料,对于Michael加成、Dieckmann缩合采用微波辐射的方法,分别对不同的微波辐射时间、微波功率、微波温度进行了试验,最佳的Michael加成条件是:微波功率设定为110～120 W,微波反应温度设定为50～55℃时,微波辐射80 min,最佳的Dieckmann缩合条件是:在微波功率...     

Spatial and temporal control of the degree of cure in polymer composite structures

This paper describes current efforts to apply spatially and temporally localized microwave processing techniques to ensure uniformity of material properties in polymer composite materials. In large polymer composite structures, high temperatures caused by exothermic resin cure can degrade the mechanical properties of the composite. In this work, resin cure temperature data was obtained during microwave processing from a series of thermocouples embedded at various lateral locations relative to the microwave source and uniformly through the thickness of the composite structure. Using this temperature information, the potential for localized microwave‐accelerated cure to reduce the occurrence of material degradation from resin over‐temperature was evaluated. In addition, a theoretical model is presented that helps elucidate the influence of the microwave parameters on the temperature profile.