全哑特级外墙面漆的研制

报道了全哑特级外墙面漆的研制 ,并对乳液、填料、颜料、助剂的筛选和实验条件进行了详细探讨。该产品具有储存稳定性好 ,性能优越 ,符合环保要求 ,达到GB/T 975 5 1995一等品要求。     

新型聚丙烯酸分散体在水性银粉漆上的应用

合成了一种新型水性聚丙烯酸分散体,介绍了其性能特点,讨论了成膜助剂对其最低成膜温度的影响。将该聚丙烯酸分散体应用于水性银粉漆中,结果发现,新型聚丙烯酸分散体所得涂膜的性能达到或超过应用指标要求。与传统的丙烯酸乳液相比,其涂层具有较好的外观、铝粉定向效果及较高的硬度,而且在很多塑料(如ABS和HIPS)底材上有良好的附着力、耐水性以及光泽度,并有非常优异的耐酒精擦拭性能。该产品以其贮存稳定、施工简便、成本低廉而获广大客户的认可。     

氯化橡胶涂料在重防腐涂装中的应用

氯化橡胶涂料属于重防腐涂料。在C4严重腐蚀大气环境条件下,氯化橡胶配套涂层有5~15 a的使用寿命,性价比高。介绍了氯化橡胶涂料的优缺点,在生产及应用中存在的问题以及改性方法。建议采用水相法、非四氯化碳溶剂法生产氯化橡胶树脂,发展高固含量氯化橡胶涂料,并扩大氯化橡胶涂料在船舶制造、非标集装箱、水利电力、化工和航标制造等行业的应用。     

Nucleation, growth and properties of nanoclusters studied by radiation chemistry: Application to catalysis

For more than three decades, extensive research work has been devoted to the unique properties of clusters. They are made of a small number (or nuclearity) of atoms or molecules only, and therefore constitute a new state of matter, with specific properties. New methods have been developed in physics and chemistry for their synthesis, their direct observation, the study of their properties, and of their crucial role in number of processes, such as phase transition, catalysis, surface phenomena, imaging. Owing to its specific approach, radiation chemistry offered first the opportunity to reveal the existence of nuclearity-dependent properties of clusters. Pulse radiolysis has then proven to be a powerful method to study the mechanisms of cluster formation, induced by irradiation as well as by chemical reduction, and the reactivity in solution or at the interfaces.     

一种测量石蜡相变乳液过冷度的新方法：平衡态比容法

石蜡相变乳液是集储热与传热于一体的新型功能流体,具有广阔的应用前景。但石蜡相变乳液在降温时会出现过冷现象,极大降低了其储热与传热的性能。采用差示扫描量热法（DSC）测量石蜡相变乳液的过冷度受到升/降温速率的影响,且升/降温速率越大,测得过冷度越大。提出一种测量石蜡相变乳液过冷度的方法——平衡态比容法。该方法通过测量石蜡相变乳液在不同温度下的比容,以确定乳液中石蜡粒子在升/降温过程中的相变温度,并进一步求解石蜡相变乳液的过冷度。实验结果表明,本研究提出的平衡态比容法能准确测量石蜡相变乳液的过冷度,并从比容变化的角度揭示石蜡相变乳液过冷现象的机理。     

Surface-grafted silica linked with l-lactic acid oligomer: A novel nanofiller to improve the performance of biodegradable poly(l-lactide)

A new surface modification method by grafting l-lactic acid oligomer onto the surface silanol groups of silica nanoparticles has been developed. The surface-grafting reaction is confirmed by IR and ²⁹Si MAS NMR analyses. TEM and SEM results show that grafted SiO₂ (g-SiO₂) nanoparticles can be comparatively uniformly dispersed in chloroform or PLLA matrix, while the unmodified SiO₂ nanoparticles tend to aggregate. The loading of g-SiO₂ nanoparticles in poly(l-lactide) (PLLA) matrix greatly improves the toughness and tensile strength of this material. In contrast, the incorporation of un-grafted SiO₂ nanoparticles into PLLA leads to the deterioration of its mechanical properties. DSC analysis shows that g-SiO₂ nanoparticles can serve as a nucleating agent for the crystallization of PLLA in the composites. SEM characterization shows the tough characteristics and great interfacial combination strength for g-SiO₂ (5 wt%)/PLLA nanocomposites.     

Structure effect of thin film polypropylene view by dielectric spectroscopy and X‐ray diffraction: Application to dry type power capacitors

This work reports on the relationship between structure and dielectric properties of biaxially oriented polypropylene. The morphology of semicrystalline bioriented isotactic polypropylene films is investigated using wide angle X‐ray diffraction and Polarized Optical Microscopy. A β‐orthorhombic structure, with a crystallinity ratio of about 46%, and “Crater” morphology of the β‐form is identified. Dielectric properties are measured by Broadband Dielectric Spectroscopy over a wide temperature range (?150 to 125°C). Since the dissipation factor of the PP is very low, special care was taken to obtain valid data. Two main relaxation processes are observed: a α‐relaxation peak associated to the glass transition temperature (Tg) at temperature about ?7°C, and a broad β*‐relaxation at about ?60°C, partly attributed to CH orientation. The variation of the dissipation factor versus sample thickness (from 3.8 to 11.8 µm) is correlated and partly explained by the increase of crystallinity ratio and lamella size at larger thicknesses. It comes out that the thinnest film seems perfectly meet the application requesting, namely lowest dissipation factor and highest permittivity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42602.     

Development of new concepts for the control of polymerization processes: Multiobjective optimization and decision engineering. I. Application to emulsion homopolymerization of styrene

This article deals with the development of a multicriteria analysis, and its application to the optimization of batch emulsion polymerization processes. This new approach in the domain of polymer reaction engineering illustrates how a multiobjective optimization aided by a genetic algorithm and using the Pareto concept of domination is useful. In this process (emulsion homopolymerization of styrene), several objectives were simultaneously required, e.g., a high quality of the resulting products together with a high productivity. The aim of this study was to find the optimal experimental conditions to obtain simultaneously the minimum reaction time and designed values for both average molecular weights and particles size. To do that, an adapted mathematical model, able to describe all the process physicochemical phenomena, was been first elaborated. The multicriteria analysis then gave a set of nondominated points with conflicting criteria. A decision support system was then developed and applied to rank the Pareto solutions set and to propose some good solutions by taking into account the decision maker's preferences. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2383–2396, 2003     

Development of new concepts for the control of polymerization processes: Multiobjective optimization and decision engineering. II. Application of a Choquet integral to an emulsion copolymerization process

In polymer industry, engineers seek to obtain polymers with prescribed end‐use properties, high productivities, and low cost. Thus, the optimization of a manufacturing process with all those goals and constraints belongs to a problem domain that aims to achieve the best trade‐off possible. This article concerns the optimization of the batch emulsion polymerization of styrene and α‐methylstyrene. An accurate model was developed to describe the complete patterns of the emulsion polymerization. Key parameters of the model were identified on the basis of batch experimental data. The model was then used to simulate, under several operating conditions, the polymerization rate, the overall conversion of monomers, and the number and weight‐average molecular weights. Amulticriteria optimization approach based on an evolutionary algorithm and the concept of dominance from the Pareto frontier theory was used. Last, a decision aid system based on the Choquet integral was proposed to determine the optimal operating conditions with the preferences of the decision maker taken into account. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Control of transport phenomena in the interior of the reforming catalyst grain: A new approach to the optimisation of the reforming process

The aim of the study was to provide favourable conditions for the transport of the reagents by modifying the porous structure and shape of the reforming catalyst grain. The study entailed the analysis of the transport phenomena and reactions that occur in spherical, cylindrical and slab-shaped catalyst grains. To upgrade the efficiency of the catalyst, use was made of analytical equations that describe the changes in the concentrations of the reagents in the catalyst grain. The equations were derived from the mass balances and the kinetic scheme assumed for the reforming process. By virtue of the coefficients of reagent diffusion, the equations are a function of the porous structure parameters and can therefore define a more or less advantageous profile of concentrations. The modification of the profile by minimising the objective function proposed in the paper leads to the reduction in the influence of diffusion resistance on the course of the reforming process. The study demonstrates that after the porous structure of the experimental catalyst had been changed, it was possible to increase its specific surface area and mechanical strength and, at the same time, noticeably improve the conditions for the transport of reagents.     

A simple model to assess the contribution of alloyed and non-alloyed platinum and tin to the ethanol oxidation reaction on Pt-Sn/C catalysts: Application to direct ethanol fuel cell performance

A simple model is proposed to evaluate the contribution of alloyed and non-alloyed platinum and tin to the ethanol oxidation reaction on Pt-Sn/C catalysts for direct ethanol fuel cells. On the basis of the model, the ethanol oxidation on partially alloyed catalysts occurs through a dual pathway mechanism, separately involving the Pt₃Sn phase and Pt-SnO_x. The model, validated by experimental data, can predict the performance of a single direct ethanol fuel cell by varying the Sn content and/or the degree of alloying of Pt-Sn/C catalysts used as the anode material.     

A new ‘Tailor-made’ methodology for the mechanical behaviour analysis of rubber-like materials: II. Application to the hyperelastic behaviour characterization of a carbon-black filled natural rubber vulcanizate

The purpose of this paper is the modelling of the mechanical behaviour of an elastomeric material, through detailed experimental and numerical procedures, specific to large strains. The experimental technique is based on in-plane kinematics measurements using a speckle extensometer, from which the whole two-dimensional field of in-plane displacements is obtained by a digital image processing [Polymer (2002)]. This part of the work concerns the identification of the constitutive equation for a carbon black natural rubber (NR) vulcanizate. We start by quoting some theoretical considerations relative to rubber elasticity and stress-softening effect, which is the counterpart of the filler reinforcement. Then, we describe the experimental procedure and present data for both non-preconditioned and preconditioned samples. Next, the identification of the constitutive law parameters using a minimization algorithm is driven. Finally, we present the validation of the constitutive model, by its implementation into the finite element code SYSTUS and the numerical simulation of the response of a double edge notched tensile (DENT) specimen.