Thermotropic polyester carbonates. III. Thermotropic polyester carbonates as self-reinforced plastics

Thermotropic polyester carbonates derived from t-butylhydroquinone, methylhydroquinone, diphenyl terephthalate, and diphenyl carbonate in the molar ratio of 50 : 50 : 55 : 45; 50 : 50 : 57.5 : 5 : 42.5 and 50 : 50 : 60 : 40 can be injection molded successfully from temperatures 10°C below melting to 30–40°C above melting. Normally the best molding temperatures are 10–20°C above melting. If the molding conditions are controlled properly, tensile strengths as high as 1.8 × 10⁴ psi, tensile moduli as high as 7.4 × 10⁵ psi, and flex moduli as high as 1.1 × 10⁶ psi can be obtained.     

Graft polymerization of vinyl acetate onto granular starch: Comparison on the potassium persulfate and ceric ammonium nitrate initiated system

This work was undertaken to discuss in depth the vital differences in the morphological development during synthesis, and properties of starch‐g‐poly‐(vinyl acetate) copolymers using two different initiators, potassium persulfate (KPS) and ceric ammonium nitrate (CAN). KPS‐initiated system gave relatively low values of grafting ratio and grafting efficiency, indicating a great tendency for the formation of poly(vinyl acetate) homopolymer (PVAc). Yet, higher values were seen for the CAN‐initiated system. Transmission electron microscope observations indicated a relatively broad distribution of latex particles for the KPS‐initiated system. The surface potential of latex particles was about ?3.5 mV, which turned out to be insufficient to maintain stability of latex particles. On the other hand, a uniform particle size distribution was found for the CAN‐initiated system, as the surface potential of latex particles was 21.5 mV. Moreover, radicals on starch molecules were generated directly through a redox reaction with positively charged ceric ion. The hydrophobic PVAc chains were thus grafted on starch, resulting in an amphiphilic graft copolymer, which provides a sufficient stabilization degree as a role of surfactant to render a relatively uniform distribution of latex particles. The synthesized starch‐g‐poly(vinyl acetate) copolymers were further converted to starch‐g‐poly(vinyl alcohol) through saponification, which were subjected to evaluations regarding the biodegradation and cell culture capability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3017–3027, 2006     

Design and control of reactive distillation for ethyl and isopropyl acetates production with azeotropic feeds

Reactive distillations for the production of ethyl acetate (EtAc) and isopropyl acetate (IPAc) are classified as the type-II process where the first column consists of a reactive zone and a rectifying section followed by a stripper [Tang et al., 2005. Design of reactive distillations for acetic acid esterification with different alcohols. A.I.Ch.E. Journal 51, 1683-1699]. Instead of using pure alcohols and acetic acid as reactants, this paper studies the effects of reactant purity on the design and control of reactive distillation. This offers significant economical incentives (by reducing raw materials costs), because ethanol forms an azeotrope with water at 90 mol% and isopropanol/water has an azeotrope at 68%. The purities of the acid is set to 95% for acetic acid (industrial grade), 87% for ethanol, and 65% for isopropanol. The results show that the total annual costs (TAC) increase by a factor of 5% for EtAc and 8% for IPAc production using reactive distillation. Next, the operability of the reactive distillations with azeotrope feeds is explored. Three disturbances, feed flow, acid feed purity, and alcohol feed composition, are introduced to assess control performance using dual-temperature control and one-temperature-one-composition control. Simulation results indicate good control performance can be achieved for reactive distillation with azeotropic feeds.     

过渡金属对Ru/海泡石催化剂加氢性能及表面性质的影响

用浸渍法制备了一系列含不同助剂Mo、Co、Mn、Cu、Zr等的Ru/海泡石催化剂，以CO₂及苯加氢为探针反应，以TPD和CS₂中毒为手段研究了助剂对Ru/海泡石催化剂加氢、反应物吸附及活化性能的影响。结果表明，助剂的加入显著地影响Ru/海泡石催化剂的催化活性，且随着反应分子的加大，这种影响随之增大；助剂对催化反应中反应物的吸附、活化过程的影响是其影响催化活性的重要原因。另外，结果还表明，助剂的加入还调整了Ru/海泡石催化剂的表面性能，但并没有改变活性中心的类型。     

Synthesis of chiral polymers having camphanediol moieties and their applications on the optical resolution of some racemates

Optically active exo-exo-2,3-camphanediol (CPO) (3) was synthesized from (+)-camphor. Chiral polymers poly(CPO-co-TDI) ( 6 ) and poly(CPO-co-IPDI) ( 7 ) were synthesized by the step polymerization of chiral compound CPO ( 3 ) with toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI). To investigate the stereo structure of the chiral polymers, two kinds of model compounds, exo-exo-2,3-di[(phenylamido)oxy]camphane ( 4 ) and exo-exo-2,3-di[(propylamido)oxy]camphane ( 5 ), related to polymers ( 6 ) and ( 7 ) were synthesized. Chiroptical characteristics and stereo structures of the chiral polymers were investigated using a circular dichroic spectrometer. The results obtained in this investigation suggest that the chiral polymers ( 6 ) and ( 7 ) have no one-handed helix conformation. The optical resolution ability as chiral adsorbent for HPLC of the chiral polymers was investigated. It was found that chiral polymers ( 6 ) and ( 7 ) are effective for the optical resolution of some racemates. © 1995 John Wiley & Sons, Inc.     

Preparation and application of fluorocarbon polymer/SiO2 hybrid materials,part 1: Preparation and properties of hybrid materials

For this study, we first prepared a fluorocarbon polymer and its hybrid materials. We found that fluorocarbon copolymers can produce hydrogen bonds with SiO₂ to form hybrid materials. We also used thermogravimetric analyzer and tested the thermostabilities of the four products, which were ranked as follows: fluorocarbon copolymer/SiO₂ hybrid material > fluorocarbon polymer/SiO₂ hybrid material > fluorocarbon copolymer > fluorocarbon polymer. In addition, we found that, due to the inorganic SiO₂ used, the number of pores and the specific surface areas of the hybrid materials both increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1140–1145, 2007     

关于化工工艺学教学改革的探讨

本文从强化课堂教学、加强实践与理论教学相结合以及强化学生工程观念等方面对《化工工艺学》课程教学方法的改革进行了探讨,提高了教学质量和教学效果,为更好地培养具有较强综合能力的化工工艺专业合格人才提供了重要保证。     

A Truncated Sum of Processing‐Times–Based Learning Model for a Two‐Machine Flowshop Scheduling Problem

Scheduling with learning effects has gained increasing attention in recent years. A well‐known learning model is called “sum‐of‐processing‐times‐based learning” in which the actual processing time of a job is a nonincreasing function of the jobs already processed. However, the actual processing time of a given job drops to zero precipitously when the normal job processing times are large. Moreover, the concept of learning process is relatively unexplored in a flowshop environment. Motivated by these observations, this article addresses a two‐machine flowshop problem with a truncated learning effect. The objective is to find an optimal schedule to minimize the total completion time. First, a branch‐and‐bound algorithm incorporating with a dominance property and four lower bounds is developed to derive the optimal solution. Then three simulated annealing algorithms are also proposed for near‐optimal solution. The experimental results indicated that the branch‐and‐bound algorithm can solve instances up to 18 jobs, and the proposed simulated annealing algorithm performs well in item of CPU time and error percentage. © 2011 Wiley Periodicals, Inc.     

From a theoretical model to a predictive simulation model of operator interaction with support systems: designing experiments to build the numerical simulation

In this paper, we will discuss a methodology developed and applied in the European ITERATE project with the objective of designing experiments that will provide data to seed the numerical model of operator behaviour in different surface transport modes: road vehicles, rail transport and ships. The experiments aim to investigate how new technologies support different types of operators in different contexts. A structured approach was adopted. Firstly, an initial selection of the systems to be investigated was made, describing the support they provide for operators. Hypotheses were formulated on the effects of operator parameters on the interaction with the systems. A final selection of systems for the experiments was made, focusing on systems providing support for collision avoidance and speed management. The operator parameters (culture, attitude and personality, experience, driver state (such as fatigue) and the demands of the task) were operationalised and piloted. The next step was the development of scenarios to be implemented in a driving simulator. In the last step, the final experiments were designed and detailed.     

Synthesis,characterization, and application of PVP/chitosan blended polymers

The purpose of this study was to research the compatibility and application of polyvinylpyrrolidone (PVP)/chitosan blended polymers. The polymers were synthesized at different weight ratios and tested using techniques such as Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis to evaluate the compatibility of the blended materials. Incompatibility occurred when the quantity of chitosan exceeded 75%. The addition of PVP was beneficial for the thermal stability of chitosan, but resulted in inferior strength performance. Furthermore, the blended polymers did not show a color‐enhancement effect, but did show elevated water absorption, chlorine resistance, and colorfastness. In addition, the treated fabrics with a higher chitosan ratio in the blended polymer had antimicrobial properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 885–891, 2006