介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

Plastics are inexpensive, easy to mold, and lightweight. These and many other advantages make them very promising candidates for commercial applications. In many areas, they have substantially suppressed traditional materials. However, the problem of recycling still is a major challenge. There are both technological and economic issues that restrain the progress in this field. Herein, a state-of-art overview of recycling is provided together with an outlook for the future by using popular polymers such as polyolefins, poly(vinyl chloride), polyurethane, and poly(ethylene terephthalate) as examples. Different types of recycling, primary, secondary, tertiary, quaternary, and biological recycling, are discussed together with related issues, such as compatibilization and cross-linking. There are various projects in the European Union on research and application of these recycling approaches; selected examples are provided in this article. Their progress is mirrored by granted patents, most of which have a very limited scope and narrowly cover certain technologies. Global introduction of waste utilization techniques to the polymer market is currently not fully developed, but has an enormous potential.

Recycling of polymers: a review

Solvent-based separation and recycling of waste plastics: A review

Surface modification and selective flotation of waste plastics for effective recycling——a review

Multi-material multilayer plastic packaging (MMPP) is widely applied in fast moving consumer goods (FMCG) combining functionalities of distinct materials. These packaging structures can enhance properties, such as resource-use efficiency and barrier performance leading to consequential benefits like a prolonged shelf-life. Nevertheless, they represent a challenge for existing recycling systems, confronting circular economy principles. This study aim was to foresight the future of recycling technologies for MMPP in the next five to ten years. Future scenarios were identified, including (1) high-performance material recycling, (2) recycling into hydrocarbons, (3) business as usual, and (4) downcycling. In-depth interviews and a feedback survey were methods used to validate the scenario matrix while defining experts' expectations towards the future. The analysis showed that distinct technologies will develop unevenly in different parts of the world. A mix of all scenarios is probable in the upcoming years, depending, essentially, on regulations and technology availability. Advanced high-performance material recycling encounters systemic bottlenecks, such as insufficient sorting technology for post-consumer waste. In contrast, chemical recycling (feedstock) is concentrating investments as a solution, requiring low input-characterization. Additionally, design for recycling trends might reduce multilayers’ complexity. A gap between recycling targets and recycling technologies was identified, representing short-term opportunities for more sustainable materials, such as bio-based.

Recycling of multi-material multilayer plastic packaging: Current trends and future scenarios

Simulation the adsorption capacity of polyvinyl alcohol/carboxymethyl cellulose based hydrogels towards methylene blue in aqueous solutions using cascade correlation neural network (CCNN) technique

Polyolefins Waste Materials Reconditioning Using Dissolution/Reprecipitation Method

Restoration of waste polymer based on lowdensity polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) is studied using the dissolution/reprecipitation method. In this technique, pure turpentine, turpentine/petroleum ether (PetE) and turpentine/benzene as solvents with different fractions and PetE and n-hexane as non-solvents were examined. Commercial polymer products (packaging food, bags, laboratory plastic materials, detergent containers) used as raw materials were optimized with model polymers. Polymer recoveries in every case were < 94%. Fourier transform infrared (FTIR) spectra and tensile mechanical properties of the samples before and after recycling were measured. Potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity), before and after recycling, using differential scanning calorimetry (DSC). The blend solvents were seen as good solvents for all polyolefins used and the dissolution temperature was less than the pure solvent at the same time. High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

Dissolution/reprecipitation technique for waste polyolefin recycling using new pure and blend organic solvents

Waste polymer reconditioning was examined by a method of dissolution/reprecipitation on low- and high-density polyethylene (PE) and polypropylene (PP). Toluene and petroleum ether, in different proportions, were used as solvents, and n-hexane was used as a non-solvent. Commercial polymer products used on an everyday basis were used with a virgin polymer, to optimize the qualities of the final product, and 98% polymer was recovered in each case. Fourier transform infrared spectroscopy (FTIR) images and tensile mechanical properties of the samples, before and after recycling, were analyzed. The potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity) before and after recycling, using differential scanning calorimetry (DSC). High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

Potential solvent for reconditioning polyolefin waste materials

The ethylene production is regarded one of the most significant issues for chemical industries and improving its production operation can bring several benefits. Thus, the market demand for ethylene production has accelerated the improvement of a more rigorous and reliable thermal cracking model of such process. In the present study, developing a rigorous mathematical model for an industrial naphtha cracker is investigated based on experimental data combining with a kinetic model describes the coke formation on the internal reactor tubes. The best kinetic model obtained is applied for predicting the products yield, the gas temperature and the optimal temperature profiles along the reactor to maximize the profit of the process. The influence of process factors on the optimal solutions (mainly, coil outlet temperature (COT), steam to naphtha ratio (S/N) and feed flow rate on the product yields have also been discussed here, and new results of the reactor with the optimal cost and temperature profile are obtained. Modeling, simulation and optimal design via optimization of the industrial thermal cracking reactor has been carried out by gPROMS software. The optimization problems are solved employing a Successive Quadratic Programming (SQP) method formulated as a Non-Linear Programming (NLP) problem.

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Arkan Jasim Hadi

Papers

Simulation the adsorption capacity of polyvinyl alcohol/carboxymethyl cellulose based hydrogels towards methylene blue in aqueous solutions using cascade correlation neural network (CCNN) technique

Polyolefins Waste Materials Reconditioning Using Dissolution/Reprecipitation Method

Dissolution/reprecipitation technique for waste polyolefin recycling using new pure and blend organic solvents

Potential solvent for reconditioning polyolefin waste materials

Optimal design of industrial reactor for naphtha thermal cracking process