Studies on synthetic-polymer plates with high surface energy. V. Diethylene glycol bis(allyl carbonate)–acrylic acid copolymer plate by vapor-phase transfer process

Synthetic-polymer plates with carboxyl group on their surface were prepared by a two-step copolymerization process transferring M₂ monomer via vapor phase. Diethylene glycol bis(allyl carbonate) (CR-39) was used as M₁ monomer, and acrylic acid was acid was used as M₂ monomer. The relations between the experimental conditions and the surface properties of the resulting plates were examined in the following terms: (1) composition of CR-39 prepolymer gel plate used and (2) concentration of benzoyl peroxide as the initiator. The plates had good water wettability and an excellent antifogging property.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. V. Casting and polymer properties of CR-39 modified monomer systems

Glassification, cast polymerization, and physical properties of monomeric system including diethylene-glycolbisallyl carbonate (CR-39) was investigated. Addition of other monomers CR-39 was investigated CR39- polyfunctional monomer and CR-39-methyl methacrylate-polyfunctional monomer systems were found to form stable glassy state applicable to radiation-induced casting and good in physical property. Two-step polymerization method consisting of pre-irradiation and post-catalytic polymerization necessary to complete casting. It was found that these newly found CR-39 modified systems could be casted efficiently in much shorter time cycle than catalytic process without forming optical strain. Physical properties of casted polymer such as impact resistance and heat durability were sufficient for practical use.     

Studies on the light-focusing plastic rod. XIII. Photocopolymerization of methyl methacrylate–vinyl esters of aromatic carboxylic acid

The light-focusing plastic rod (LFR) was prepared by the photocopolymerization of methyl methacrylate (MMA) with vinyl phenylacetate (VPAc) and vinyl benzoate (VB), using benzoyl peroxide (BPO), benzoin (BN), and benzoin methyl ether (BME) as an initiator. The LFR with high transparency and steep refractive-index distribution was obtained using the MMA–VPAc pair and the BME. The difference in the index distributions under BPO, BN, and BME initiations was clarified in terms of the photoinitiation rate and the accompanying thermal polymerization during the photocopolymerization process. The light scattering intensity from the LFR was related to the heterogeneity of the copolymer composition and the compatibility between the M₁ and M₂ polymers. The comparison of the light scattering theory with the experimental data indicated that the much less scattering intensity from the MMA–VPAc LFR than the MMA–VB LFR should be attributed to the good compatibility between the MMA and VPAc polymers, and scarcely attributed to the index difference between the VPAc and VB polymers.     

Studies on synthetic polymer plates with high surface energy. III. Diethylene glycol bis(allyl carbonate)–unsaturated sulfonic acid system

Synthetic polymer plates (GPs) with high surface energy were prepared by the two-step copolymerization process previously reported, using diethylene glycol bis(allyl carbonate) (CR-39) as M₁ monomer and unsaturated sulfonates [sodium vinyl sulfonate (VS^?Na⁺), potassium styrene sulfonate (StS^?K⁺), and sodium 2-sulfoethyl methacrylate (SEM^?Na⁺)] as M₂ monomer. The contact angle (θ_H) of water for the acid-treated (immersed in an aqueous 0.1 N HCl solution for 2 h) GPs decreased in the order StS^?K⁺, VS^?Na⁺, and SEM^?Na⁺. In the case of M₂ = SEM^?Na⁺, the θ_H value was about 20°. By adding NaCl in the immersion solution and changing the pH of the immersion solution, the θ_H values for the CR-39–SEM^?Na⁺ GPs were lowered to 18.9 and 13.1°, respectively. The θ_H values for the above GPs were smaller than those for the CR-39–acrylic acid or the CR-39–methacrylic acid GPs in the previous report, whereas the contact angle (θ_Na) of water for the former after alkali treatment (immersed in an aqueous 0.1 N NaOH solution for 2h) was larger than those for the latter. The former had durability of water wettability superior to the latter because of the difference in dissociation characteristic of the respective functional group.     

Rheological properties of styrene‐co‐2‐furfuryl methacrylate copolymers

The copolymerization of styrene with furfuryl methacrylate (FMA) led to a very significant molecular weight increase and to branching, as measured by standard gel permeation chromatography (GPC) and tri‐angle laser light‐scattering GPC. This increase was also confirmed by dynamic mechanical spectroscopy. Extensional viscosity analysis showed that styrene‐co‐2‐furfuryl methacrylate copolymers exhibited strain hardening at low strain rates. This strain hardening is explained as a result of the copolymers' polydispersity features rather than a result of their topology. The presence of strain hardening in extensional viscosity experiments is believed to be advantageous in the production of foamed materials with lower densities. A reduction in density was corroborated by foaming experiments on a development extrusion line. The mechanism of density lowering was related more to cell growth than to increased nucleation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1062–1071, 2005     

Conventional and RAFT miniemulsion copolymerizations of butyl methacrylate with fluoromethacrylate and monomer reactivity ratios

Reversible addition fragmentation chain transfer (RAFT) mediated and conventional miniemulsion copolymerizations of butyl methacrylate (BMA) with fluoromethacrylate (FMA) were carried out at 70°C with potassium persulphate as initiator. The kinetics of the copolymerizations was investigated comparatively. Copolymer compositions at low conversion levels were determined by ¹H NMR and FTIR spectra techniques. In the presence of RAFT agent 2‐cyanoprop‐2‐yl dithiobenzoate, the copolymerization of BMA with FMA in miniemulsion was obviously retarded. The copolymerization exhibited typical features of controlled molecular weights and narrow polydispersities. The reactivity ratios were evaluated by Kellen‐Tudos (K‐T) method, which yields the apparent reactivity ratios: r_BMA = 0.73 and r_FMA = 0.75 in conventional copolymerizations, and r_BMA = 0.65 and r_FMA = 0.70 in CPDB‐mediated system. The results show that the monomer FMA with a perfluoroalkyl side chain is slightly more reactive than BMA, and the copolymerizations process have a tendency to crosspropagate and to produce a higher FMA content in the copolymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Studies of reactions with polymers. I. The reaction of maleic anhydride with PVA and the properties of the resultant

Graft copolymerization of maleic anhydride (MA) onto PVA was carried out both in the presence and absence of the initiator. In the former case, the resultant was a copolymer containing a carboxylic acid and a keto-olefinic side chain. Therefore, the reaction product, viscosity, gel content, and mechanical properties differed from the resultant of the latter, which was obtained by esterification of PVA by MA. Both resultants showed polyelectrolytes characteristics. The dependence of the grafting percentage on the concentration of the initiator, the concentration of the monomer, the reaction temperature, and the reaction medium was studied. Grafted copolymers after heat treatment showed remarkable mechanical strength in the wet state when compared with original PVA.     

Graded‐index plastic optical fiber with high mechanical properties enabling easy network installations. II

It was shown how high mechanical strength should be provided in the high numerical aperture (NA) graded‐index plastic optical fiber (GI POF). In this newly developed GI POF, a copolymer of methyl methacrylate (MMA) and 2,2,2‐trifluoroethyl methacrylate (3FMA) was used to increase the NA. The GI POF we proposed previously was composed of a PMMA homopolymer cladding and a doped PMMA core. It was previously shown that substituting the copolymer P(MMA–3FMA) for the PMMA as the cladding material made little change in the fiber's light‐transmission characteristics. This study focused on mechanical flexibility, which is one of the most important advantages of the POF. It was found that the P(MMA–3FMA)‐clad GI POF had almost the same or superior mechanical strength in addition to the excellent light‐propagation characteristics. It was also found that such excellent mechanical properties were achieved using a small dopant concentration and optimum heat‐drawing conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 410–416, 2004     

Lewis酸存在下的自由基共聚合——Ⅲ.GeCl_4或BCl_3存在下的乙酸乙烯酯与丙烯酸甲酯的共聚行为

与前报乙酸乙烯酯(VAc)与丙烯酸共聚体系相比,VAc与丙烯酸甲酯(MA)在GeCl_4或BCl_3存在下,由自由基聚合不能得到交替共聚物,通过改变单体配比也不会出现最大反应速率。紫外光谱分析证实,BCl_3和GeCl_4均能与MA形成配位化合物,对MA-VAc-BCl_3体系则能发生阳离子聚合反应,并生成凝胶。     

Vibrational spectroscopic investigation of light‐induced polymerization process of epoxy resin,polytetrahydrofuran and spirobislactone

The light‐induced polymerization process of bisphenol F diglycidyl ether (BFDGE), 5,5′‐dicarboxylic‐7,7′‐dioxo‐2,2′‐spirodi(benzotetrahydrofuran) (DCSBL) and polytetrahydrofuran (pTHF‐250) was studied. 4‐[(2‐Hydroxytetradecyl)oxy]phenyl‐phenyliodoniumhexafluoroantimonate, camphorquinone and ethyl 4‐dimethylaminobenzoate were used as a photoinitiator system. The polymerization process was induced by light and monitored using Fourier transform infrared spectroscopy. A novel combination‐initiation polymerization process was proposed: first, cationic copolymerization of BFDGE and pTHF‐250 was initiated by the photoinitiator system and heat was released by this polymerization; then, copolymerization of BFDGE and DCSBL was induced by that heat while pTHF‐250 served as an anionic initiator. Copyright © 2007 Society of Chemical Industry     

Immobilization of disperse red 1 onto polydiethyleneglycol-bis-allylcarbonate (CR-39) radiation grafted with poly(acryloyl chloride)

Abstract Acryloyl chloride (AC) was radiation grafted from 30% solution of monomer in toluene onto polydiethyleneglycol-bis-allylcarbonate (CR-39) by their simultaneous -iradiation. The grafting process was more efficient at dose rate of 4.4 kGy/h as compared with 0.4 kGy/h, and grafting values of 15-18% were achieved at 2.2-5.5 kGy. Subsequent immobilization of disperse red 1 (DR1) onto the grafted polymer was carried out from 0.02 M solution of this dye in dichloroethane, and the immobilized DR1 yield increased with the grafted polyAC value. Surfaces of the starting and modifed CR-39 were characterized with the FTIR-ATR spectroscopy and atomic force microscopy. An essential difference in chemical structure and topography of the CR-39 surface before and after the DR1 immobilization has been shown. The colourless plates of CR-39 became red after the DR1 immobilization, and the color intensity increased with the dye content. Changes in visible absorption spectra of the immobilzed DR1 caused by the photoinduced trans-cis isomerization of this dye were discussed.     

On the copolymerization of styrene and methyl methacrylate with some monomeric benzanthrone-derivative dyes

The copolymerization of styrene and methyl methacrylate with two monomeric fluorescent dyes, benzanthrone derivatives, have been investigated. The most suitable parameters of the process were determined. The copolymers obtained had an intensive stable to solvent color and fluorescence, due to the chemical bonding of the dye to the polymer's chain. It was established that between 85 and 95% of the dye reacted in the process. The course of the copolymerization was investigated by gel permeation chromatography, and the influence of the dyes on the molecular weight and polydispersity of the polymers was determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 91–97, 1997     

The FluxMax approach for simultaneous process synthesis and heat integration: Production of hydrogen cyanide

Resource and energy efficiency are essential in process synthesis of chemical plants as they combine economic with ecological benefits. The two main targets of the process synthesis problem—mass and energy flux optimization—are typically split into two steps: single unit optimization and subsequent energy integration preventing the identification of the globally optimal solution. This article presents a single-step procedure for resource-efficient process synthesis through simultaneous heat and mass flux optimization called FluxMax approach (FMA), which is demonstrated for the production of hydrogen cyanide (HCN). The impact of simultaneous heat integration on the optimal process structure is demonstrated and two resource-optimal processes for HCN production are identified consisting of a combination of different reactor and recycling strategies reducing total variable cost by 68%. For convex objective functions, the globally most resource-efficient process is identified highlighting the potential of the FMA for site planning and retrofitting of existing plants.     

硅烷交联聚氯乙烯的制备和性能

对由悬浮共聚合成的氯乙烯／乙烯基三乙氧基硅烷共聚树脂的水解交联行为和交联聚氯乙烯的性能进行了研究。结果发现，通过聚合过程添加pH调节剂可得到凝胶含量很低的氯乙烯／乙烯基三乙氧基硅烷共聚树脂；该类共聚树脂加工后有一定程度交联发生，凝胶含量随共聚树脂中乙烯基三乙氧基硅烷含量增加而增加；当加工样品在水中浸渍后凝胶含量又有较大幅度提高，说明水解交联的发生；交联后PVC高温力学性能和耐热变形性提高。     

折流杆换热器在压缩机级间冷却上的应用

一种新型的Ｕ形管式折流杆换热器已成功地替代了Ｈ２２（Ⅲ）氮、氢压缩机的套管式冷却器。新设备的体积、重量和压降分别为原设备的１／６、１／４和１／３。分析介绍了这一新设备的特性及应用实例     

乙烯与4-甲基-1-戊烯在现有HDPE工艺上共聚合的可行性探讨

采用四氯化钛-乙氧基镁催化体系的Ziegler高效催化剂(SG010-B型),在现有工艺上对乙烯与4-甲基-1-戊烯共聚合的可行性进行了探讨,认为在现有聚合工艺上,采用4-甲基-1-戊烯作为改性HDPE的共聚单体是适宜的。由该聚合工艺制得的改性HDPE树脂具有良好的加工性能和机械性能,其制品比其它HDPE的共聚产品具有质量轻、透明性好、耐热性高等优点。     

醇盐锆水解制备ZrO2粉体的研究

选用实验室合成的醇盐锆为前驱体，采用ｓｏｌ－ｇｅｌ工艺制备了氧化锆粉体。利用ＴＥＤ、ＤＴＡ、ＸＲＤ、ＩＲ光谱等手段研究了水解过程及水解产物的热处理过程，若适当控制醇盐锆水解条件，可制成亚微米级分布均匀的超细粉体。     

Macroporous styrene-divinylbenzene copolymers: Formation of stable porous structures during the copolymerization

Summary The variation of the pore structure of styrene-divinylbenzene (S-DVB) copolymer beads depending on the polymerization time was investigated. Macroporous S-DVB copolymer beads with 10 mol % DVB content were prepared in the presence of cyclohexanol as a diluent. It was found that the stable pores in S-DVB copolymers mainly form at an early stage of the copolymerization, i.e., at the gel point. Thus, the early phase separated portions of the network, where the crosslink density is locally high, do not collapse on drying and illustrate the stable part of the porosity of S-DVB copolymers. The number of stable pores does not change much during the whole course of the copolymerization. The maximum porosity first decreases on rising the post-gelation time due to the decreasing degree of dilution of the gel phase. Then, it increases continuously due to the increasing crosslink density of the gel. The pores formed at a later stage of the copolymerization are unstable and they collapse during the drying process. This is due to the lower crosslink density of the network regions forming later. Received: 27 February 1998/Revised version: 18 June 1998/Accepted: 18 June 1998     

Kinetics of the free-radical copolymerization of methyl methacrylate/ethylene glycol dimethacrylate: 1. Experimental investigation

An experimental investigation was made of the kinetics of the bulk free-radical copolymerization of methyl methacrylate (MMA) and the divinyl monomer ethylene glycol dimethacrylate (EGDMA) initiated with AIBN at 70°C for levels of EGDMA of 0–25 wt% and chain transfer agent (CBr₄) levels of 0–1 wt%. The conversion of monomers to sol and crosslinked gel was measured by gravimetry using Soxhlet extraction. This provided measurements of monomer conversion at the gelation point as a function of EGDMA and CBr₄ levels and the weights of sol and gel as a function of time and monomer conversion. The experimental data are interpreted in terms of the pseudo-kinetic rate constant method in Part 2 of this series.     

Die Polymerisation von Lactamen. IV. Die anionische Copolymerisation von 6-Caprolactam mit 8-Caprylolactam

Conditions were defined for preparing homogeneous castings based on copolymers of 6-caprolactam and 8-caprylolactam under conditions of the low-temperature adiabatic copolymerization of the two lactams below the melting point of polymeric products (catalyst: sodium salt of lactams, activator: N-acetyl-6-caprolactam). The content of 8-caprylolactam in the copolymer cannot exceed 30 mole-% owing to its high polymerization heat and to the dependence of the copolymer melting point on the concentrations of the two lactams; the homopolymerization of the 8-caprylolactam cannot be accomplished under these conditions. The copolymer melting point exhibits a minimum in the region of the equimolar ratio of the two lactams. Further, the temperature dependence of the 8-caprylolactam specific heat was determined over an interval of 100 to 226°C (C_p = 0.2543 + 0.0007 T). The copolymerization rate of the anionic process increases with increasing content of 8-caprylolactarn, in accordance with differences of several orders existing between homopolymerization rates of the two lactams. The content of water extractable portions in the copolymers drops proportionally to increasing content of 8-caprylolactam, similarly as in equilibrium copolymers prepared by the hydrolytic copolymerization.