Development of a new advanced process for manufacturing polyacetal resins. Part I. Development of a new process for manufacturing highly concentrated aqueous formaldehyde solution by methylal oxidation

A new technology for the production of highly concentrated aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mol of water per 1 mol of formaldehyde, methylal oxidation produces only 1 mol of water for every 3 mol of formaldehyde. Thus, the output from methylal oxidation is more than 70% formaldehyde compared with 55% from methanol oxidation. For this purpose, basic research for methylal synthesis was tried and the world's first commercial production of methylal was accomplished. Using this methylal, the world's first technology of methylal oxidation for manufacturing highly concentrated aqueous formaldehyde was established by development of a new methylal oxidation catalyst composed of iron, molybdenum, and a third component. This highly concentrated aqueous formaldehyde is then fed to the acetal homopolymer and copolymer plant whose combined capacity is 35,000 tons/years. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of some novel copolymer resins. III

In continuation of our endeavor to develop synthetic resins of improved properties and performance, we report here the synthesis of mixed copolymer resins by the condensation of resorcinol, aniline, and formaldehyde with ortho-, meta-, and para-phenylenediamine separately. The resins were characterized by infrared (IR) and thermogravimetric analysis (TGA). The mixed copolymer resins were found to have superior thermal stability over conventional phenol–CH₂O and resorcinol–CH₂O resins. The solubility behavior of the resins showed that they are resistant to common solvents. However, they are soluble in concentrated H₂SO₄ and HNO₃, but insoluble in concentrated HCl. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 68: 2183–2187, 1998     

A new process aid for melt compounding of PVC with ethylene copolymer resins

Ethylene copolymer resin (ECR) modifiers are solid, high molecular weight, permanent plasticizers for PVC. During the melt compounding step, the low melting ECR (m.p. ～50°C) melts first forming a relatively low viscosity phase in which the higher melting (Tg ～80°C) and more viscous PVC powder grains (～150 μm in diameter) are suspended. Under these conditions, it is sometimes difficult to get enough shear energy into the system to break down, or flux, all of the PVC grains into unagglomerated primary particles (～1 μm diameter). The remaining grains appear as gel-like heterogeneities, in the final blend, that can produce rough, pimpled extrudates with reduced physical properties. This paper describes the use of a new experimental process aid that significantly improves homogenization, during the melt compounding process, leading to improved product quality and/or production rates.     

Particle features of poly(vinyl chloride) resins prepared by a new heterogeneous polymerization process

The heterogeneous polymerization of vinyl chloride monomer (VCM), with n‐butane as the reaction medium, was used to prepare poly(vinyl chloride) (PVC) resins. The particle features of the resulting resins and the particle formation mechanism of the polymerization process were investigated. The PVC resins prepared by the new polymerization process had a volume‐average particle size comparable to that of suspension PVC resins and a lower number‐average particle size. From scanning electron micrographs, it could be seen that the new PVC resins had a regular particle shape and a smooth surface with no obvious skin. They also had a high porosity. The new PVC resins were composed of individual and loosely aggregated primary particles. The diameter of the primary particles in the top layer of the grains was smaller than that of the primary particles in the center part of the grains. On the basis of the particle features of these PVC resins, a particle formation mechanism for the new polymerization process was proposed. PVC chains precipitate from a VCM/n‐butane mixed medium to form primary aggregates at a very low conversion, and the primary aggregates of the PVC chains aggregate to form primary particles, which further aggregate to form grains. The primary particles and grains grow by the capture of newly formed PVC chains and their primary aggregates and by polymerization occurring inside the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 954–958, 2003     

Modeling of a Buss‐Kneader as a polymerization reactor for acrylates. Part II: Methyl methacrylate based resins

The Buss‐Kneader has proven to be a suitable reactor for the polymerization of acrylates. In this second part, the polymerization of methyl methacrylate and the ter‐polymerization of methyl methacrylate (MMA), hydroxyethyl methacrylate and n‐butylmethacrylate is carried out in a pilot Buss‐Kneader. The reactor had to be pressurized up to about 10 bars to avoid evaporation of MMA. Instabilities in output rate and temperature profiles were observed as a result of fluctuating die pressures. Because of good mixing there may be no diffusion limitation for radicals. As a result, even at high conversions, no gel effect was observed.     

Preparation and properties of Si-containing copolymer for near-UV resist. III. Maleimide/silylstyrene copolymer

Poly(maleimide-alt-p-trimethylsilyl-α-methylstyrene) (α-PMTMMS) and poly(male-imide-alt-p-trimethylsilylstyrene) (PMTMSS) were synthesized for positive/negative near-UV resists in the containing of diazonaphthoquinone sulfonate (DNS). The electron-rich styrenic monomers tend to undergo alternating copolymerization with an electron-poor maleimide monomer. The chain-stiffening effects of the maleimide and α-methylstyrene group were responsible for high thermal stabilities. A higher glass transition temperature of 226°C was found in α-PMTMMS. Lithographic positive/negative images were obtained that were stable to temperatures higher than 200°C. Excellent solubility in aqueous base was observed with PMTMSS at 10.3 wt % silicon content and an oxygen-plasma etching rate of 1:12 compared to hard-baked HPR–204. © 1993 John Wiley & Sons, Inc.     

一种新型重油催化裂化抗镍钝化剂的开发研究

采用浸渍法在催化裂化催化剂上引入能抗重金属污染的水溶性钝镍剂(有效元素代号为A₁和A₂),以钝化重金属Ni对催化剂的毒性;通过TPR、XRD等检测手段,阐明其钝镍机理。研究表明,A₁和A₂两种钝镍元素复配具有协同作用,适宜原子比的钝镍剂能起到有效钝镍效果。在镍含量高于1.0%的平衡剂上,加入钝镍剂与不加钝镍剂相比较,催化剂活性指数提高8.48个单位,比氢气量相对下降52.92%,比积炭下降37.65%。实验优选了加入钝镍剂有效元素的最佳原子配比。     

本体法与悬浮法PVC树脂生产工艺的比较及在管件生产中的优势

比较了本体法PVC7型树脂与悬浮法PVC-SG7型的生产工艺,介绍了本体法PVC树脂的质量、塑化性能和加工性能等在管件生产中的优势。     

Microspheres and microcapsules,a survey of manufacturing techniques: Part III: Solvent evaporation

A methodological survey of microsphere formation and microencapsulation techniques based on solvent extraction/evaporation techniques is presented. Thus, basic features of solvent extraction and solvent evaporation processes, including droplet formation, droplet/particle stabilization, and solvent removal, are outlined. Preparation of a wide range of microspherical and microcapsular products based on biodegradable polyesters, polysaccharides, and nonbiodegradable polymers are discussed. Dependence of microcapsule characteristics on manufacturing parameters, as well as performance evaluation of microspherical and microcapsular products, are also briefly covered.     

Development of polymer blend morphology during compounding in a twin-screw extruder. Part III: Experimental procedure and preliminary results

Currently, selection of screw configurations as well as the operating conditions for compounding polymer blends with desired morphology in a co-rotating twinscrew extruder is an art based on experience. In this paper a quenching section of a twin-screw extruder is described. The section may replace any segment of the extruder barrel. It allows, on the one hand, a regular operation of the machine, and on the other, a rapid quenching and removal of blend specimens for morphology analysis from any place along the extruder barrel and at any time of the blending. The experimental observation of development during compounding of polymer blends enables verification and improvement of the theoretical model, aimed at predicting and controlling the size and polydispersity of the minor phase. Development of the predictive model for blend morphology will provide a valuable guide to the polymer processing industry. The preliminary data were collected using polystyrene/high density polyethylene (PS/HDPE) blends at low concentration of the dispersed phase, 5 wt% of either PS or HDPE. It was observed that the viscosity ratio, blend composition, screw configuration, temperature, throughput, and screw speed significantly influence the blend morphology.     

Radiation-induced polymerization of ethylene in a pilot plant. II. Development of wet-wall process

Radiation-induced polymerization of ethylene using tert-butyl alcohol aqueous solution as a medium was carried out in a pilot plant with 10 liter reactor at pressures of 100 to 400 kg/cm², ethylene feed rates of 1.2 to 11.8 kg/hr, medium feed rates of 0 to 100 liter/hr, dose rates of 0.6 × 10⁵ to 1.4 × 10⁵ rad/hr, and at room temperature. The space-time yield and molecular weight of polymer were in the range of 1.2 to 16.7 g/liter hr and 6 × 10³ to 2 × 10⁵, respectively. The space-time yield and molecular weight increased with pressure and mean residence time. The space-time yield was the maximum at an ethylene molar fraction of 0.5. The produced polymer was continuously taken out from the high-pressure system as a slurry. The amount of deposited polymer to the reactor wall was markedly decreased, and five full days continuous operation was successfully performed with the space-time yield of 13.5 g/liter hr.     

Synthesis and characterization of a new block copolymer: Poly(butylene terephthalate-co-olefin) application on PP/PBT blend and PBT homopolymer

The synthesis of a new block copolymer was investigated by the condensation of terephthaloyl chloride, hydrogenated α,ω-dihydroxy polybutadiene and butanediol. The resulting (PBT) product is termed as the hard segment, and the hydrogenated α,ω-dihydroxy poly-butadiene is termed as the corresponding soft segment. This block copolymer was characterized by FTIR, ¹H and ¹³C-NMR, DSC, and SEC. Quantitative estimations of the contents of block segments have been carried out by NMR. The product was used either to increase the properties of PBT/PP blends or the impact strength of PBT. In both cases the mechanical properties are described. © 1995 John Wiley & Sons, Inc.     

Synthesis of a new iron (III) porphyrin acrylate-styrene copolymer and its catalysis for hydroxylation of cyclohexane

A new iron (III) porphyrin acrylate-styrene copolymer, P[(PorFe)A-S], was synthesized by the reaction of iron (III) porphyrin acrylate with styrene and characterized by UV-Vis, Infrared spectra (IR), inductively coupled plasma-atomic emission spectrometry (ICP) and molecular weight determination. Its catalytic activity in the hydroxylation of cyclohexane for model cytochrome P450 in the P[(PorFe)A-S]-O₂ ascrobate-thiosalicylic acid system has been studied. It was found that the P[(PorFe)A-S] has a higher catalytic activity than non-supported iron (III) porphyrin and its high catalytic activity remained in reuse. The catalytic activity of P[(PorFe)A-S] was discussed in the view of the microenvironment of iron (III) porphyrin. It is proposed that the atalytic activity of the P[(PorFe)A-S] may be further enhanced by construction of a homophase catalytic system containing the iron (III) porphyrin acrylate-styrene copolymer.     

Synthesis of a new iron(III) porphyrin acrylate-styrene copolymer and its catalysis for hydroxylation of cyclohexane

A new iron(III) porphyrin acrylate-styrene copolymer, P[(PorFe)A-S], was synthesized by the reaction of iron(III) porphyrin acrylate with styrene and characterized by UV-Vis, Infrared spectra (IR), inductively coupled plasmaatomic emission spectrometry (ICP) and molecular weight determination. Its catalytic activity in the hydroxylation of cyclohexane for model cytochrome P450 in the P[(PorFe) A-S]-O₂-ascrobate-thiosalicylic acid system has been studied. It was found that the P[(PorFe)A-S] has a higher catalytic activity than non-supported iron(III) porphyrin and its high catalytic activity remained in reuse. The catalytic activity of P[(PorFe)A-S] was discussed in the view of the microenvironment of iron(III) porphyrin. It is proposed that the catalytic activity of the P[(PorFe)A-S] may be further enhanced by construction of a homophase catalytic system containing the iron(III) porphyrin acrylate-styrene copolymer. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(1): 61–63 [译自: 中山大学学报 (自然科学版)]     

氯磺酸合成新工艺的开发与应用

1气相法合成工艺氯磺酸是三氧化硫的延伸产品,国内现有的氯磺酸生产装置均使用三氧化硫气体(如一次转化出口炉气、加热蒸发发烟硫酸产生纯SO_3,气体配用二次转化出口炉气、加热蒸发发烟硫酸产生的纯SO_3气体等),与来自曼海姆法硫酸钾装置的氯化氢气体[(?)(HCl)≥30%]或者氯碱装置氯化氢气体[(?)(HCl)约95%]或者硫酸-盐酸氯化氢发生装置氯化氢气体[(?)(HCl)约100%]在130～230℃下反应,合成气态氯磺酸,再经过冷凝分离得到液态氯磺酸产品。气相法合成工艺存在的问题主要有:a.尾气     

Selective localization of multi-wall carbon nanotubes in homopolymer blends and a diblock copolymer. Rheological orientation studies of the final nanocomposites

In this study, pristine as well as polystyrene (PS) and poly(2-vinylpyridine) (P2VP) functionalized multi-wall carbon nanotubes (MWCNTs) were selectively incorporated in homopolymer binary blends of PS/P2VP and diblock copolymer (BCP) of the PS-b-P4VP type [P4VP: poly(4-vinylpyridine)]. Studies on the blends verified the chemical affinity of PS and P2VP grafted MWCNTs to the corresponding phase. Based on the results obtained from the blend systems, MWCNTs were incorporated in a PS-b-P4VP copolymer matrix with lamellar morphology and large amplitude oscillatory shear (LAOS) experiments were performed to achieve orientation of the BCP lamellae. The PS grafted MWCNTs (MWCNT-g-PS) were selectively sequestered in the PS phase and the P2VP grafted MWCNTs (MWCNT-g-P2VP) in the P4VP phase of the diblock copolymer. Unfunctionalized pristine MWCNTs were localized on the PS phase of the blend system and no special preference was observed towards the diblock copolymer PS domains. Small angle X-ray scattering (SAXS) analysis revealed the orientation of the alternating lamellae formed by the diblock copolymer when studied by LAOS. The localization of PS and P2VP grafted MWCNTs on the corresponding blend and BCP phase was also verified by transmission electron microscopy (TEM) studies.     

Development of a new cleaner production process for cassava ethanol

A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation exchange resin before being recycled as process water to make mash for the next ethanol fermentation batch. Thuswastewaterwas eliminated and freshwater and energy consumptionwas significantly reduced. To evaluate the new process, ten consecutive batches of ethanol fermentation and anaerobic digestion at lab scale were carried out. Average ethanol production in the recycling batches was 11.43% (v/v) which was similar to the first batch,where deionized (DI)waterwas used as process water. The chemical oxygen demand (COD) removal rate reached 98% and the methane yield was 322 ml per gramof COD removed, suggesting an efficient and stable operation of the anaerobic digestion. In conclusion, the application of the new process can contribute to sustainable development of the cassava ethanol industry.     

Development of a new electroplating process for Ni-W alloy deposits

In the present work, the effect of the complexing agents citrate, glycine and triethanolamine (TEA) on the electrodeposition of Ni-W layers from electrolytes based on NiSO₄ and Na₂WO₄, is investigated. The investigations include measurement of the current efficiencies, determination of the tungsten content in the electrodeposits (by energy dispersive X-ray analysis), voltammetry studies and characterization of complex formation by UV-spectrometry. High W content and current efficiency could be realized by using electrolytes containing all of the three complexing agents. The results show that small amounts of glycine in a citrate-triethanolamine based electrolyte positively influences both the mass-transfer and the deposition potential.