Ultrasonic Degradation and Copolymerization of Poly (Vinyl Alcohol) with Acrylonitrile

The ultrasonic degradation of poly(vinyl alcohol) (PVA) in aqueous solution and copolymerization of PVA with acrylonitrile (AN) were studied. It is confirmed that the rate of degradation of PVA follows the kinetic equation suggested by Baramboim. Both water-soluble and water-insoluble copolymer can be obtained by changing the irradiation time or the amount of AN added to the aqueous solution of PVA. The structure of the copolymer was identified by IR, MS, PGC, and x-ray diffraction. The copolymer prepared is mainly a block one. By irradiating 2% PVA/AN (1/1.6, w/w) at 20 ± 1°C and 21. 5 kHz with 490 W for 28 min, the yield of water-soluble copolymer is 25.49%, the AN content in which is 13.98%. After 100 min, with the weight ratio between PVA and AN 1/4, the yield of the water-insoluble copolymer amounted to 296.01%, the AN content in which is 75.56%.     

Isolation and characterization of microorganisms degrading nylon 4 in the composted soil

Two kinds of microorganisms, a bacterium (KT-1 strain) and a fungus (KT-2 strain), degrading nylon 4 (polyamide 4), which was easily prepared by the anionic ring-opening polymerization of 2-pyrrolidone, were isolated from the composted soil with the utilization of enrichment cultures and the culture using nylon 4 as a carbon source. KT-1 and KT-2 strains were identified as neighboring species to Stenotrophomonas sp. and Fusarium sp., respectively, by their morphological properties and the nucleotide sequences. These strains were confirmed to grow in the culture medium containing nylon 4 powders as a carbon source. In addition, nylon 4 film was decomposed in both mineral media containing KT-1 and KT-2 strains, respectively, and disappeared within two months. The MALDI TOF-MS analysis of nylon 4 recovered during the biodegradation test suggest that the isolated KT-2 strain recognize the acyllactam or carboxy chain end and degrade them or their neighboring amide bond.     

Copolymerization of Diethyl Vinyl Phosphate with Vinyl Acetate and Acrylonitrile

Free radical-initiated copolymerization of diethyl vinyl phosphate (DEVPA) with vinyl acetate (VAc) and acrylonitrile (AN) was studied. The monomer reactivity ratios for the monomer pairs, determined at 60°C using benzoyl peroxide as an initiator, are: r₁(VAc) = 0.95, r₂(DEVPA) = 0.93; r₁(AN) = 6.6, r₂(DEVPA) = 0.049. The values of the Alfrey-Price constants, Q and e, for DEVPA were calculated to be 0.025 and 0.13, respectively, from the VAc system, and 0.026 and 0.14, respectively, from the AN/DEVPA pair. These results indicate that the general reactivity of DEVPA is almost the same as that of VAc and that the diethylphosphate group is a stronger electron-attracting group than the acetoxy group. The intrinsic viscosity and number-average molecular weight of copolymers decreased as their content of DEVPA units increased, indicating a high degree of chain transfer caused by DEVPA.     

The Spontaneous Copolymerization of Indene with Polar Vinyl Monomers in the Presence of Zinc Chloride

Indene (ID) was found to copolymerize spontaneously with polar vinyl monomers containing a nitrile or ester group in the presence of ZnCb and to give rise simultaneously to its cationic homopolymer in the latter comonomer. The formation of a 1:1-charge transfer complex between ID with acrylonitrile coordi-nated to ZnCl₂ ((AN)c) was confirmed by UV-spectroscopic studies and the equilibrium constant for it was estimated to be 0.121 L/mol in AN at 25°C. The overall activation energy for the copolymerization with (AN)c was obtained to be ～9.8 kcal/mol. An increasing amount of ZnCl₂ in AN resulted in increases in the copolymerization rate, viscosity, and alternating tendency of the copolymer. The addition of 1, 1-diphenyl-2-picrylhydrazyl to the System ID-(AN)c retarded the copolymerization and induced a cationic polymerization of ID. Further, terpolymers containing ～50 mol % AN were formed spontaneously in the System ID-styrene-(AN)c. Comparing these results with the corresponding ones obtained for 1,3-cyclodienes as donor monomer reported previously, a discussion is given on the reactivity of ID-(AN)c complex in the initiation and the propagation of the copolymerization. The mechanism of the attendant cationic polymerization of ID is briefly considered.     

Radical copolymerization of 2,2,2-trifluoroethyl methacrylate with cyano compounds for dielectric materials: Synthesis and characterization

The copolymerization of cyano (nitrile) monomers and a fluoroalkylmethacrylate is used to develop new dielectric polymers containing C-CN and C-F substituents. Methacrylonitrile (MAN), acrylonitrile (AN) and methylvinylidene cyanide (MVCN) were chosen as cyano monomers. 2,2,2-Trifluoroethyl methacrylate (MATRIF) was used as a fluorinated comonomer. The copolymers based on cyano monomers such as AN, MAN or MVCN, and MATRIF comonomers were synthesized by radical process initiated by AIBN. The yields of the copolymerizations were ranging between 40 and 60%. These copolymers were characterized by ¹H, ¹³C, ¹⁹F NMR and IR spectroscopy which showed that the percentages of incorporation of AN and MAN in the copolymers were 45%. However, only 5% of MVCN was incorporated into poly(MVCN-co-MATRIF) copolymer. Thermogravimetric analyses showed that the thermal decomposition occurred from 200, 230 or 240 °C for copolymers of MVCN, MAN or AN, respectively, and indicated that the process of degradation depends on the nature of cyano monomer.     

Study on copolymerization behavior of 2-substituted 4-methylene-1,3-dioxolane with maleic anhydride and acrylonitrile

Copolymerizations of 4-methylene-2-styryl-1,3-dioxolane ( 1 ) and 4-methylene-2-methyl-2-styryl-1,3-dioxolane ( 2 ) with electron-deficient monomers, such as maleic anhydride (MA) and acrylonitrile (AN) were investigated. Only homopolymer of 1 was obtained from the copolymerization of 1 with MA in the presence or absence of AIBN. The copolymerization of 1 and AN with AIBN as initiator gave a copolymer consisting of three kinds of repeating units. Reaction of 2 with MA gave a crystalline product with and without AIBN present. A nine-membered ring structure is proposed for this product based on its IR, UV, proton and ¹³C-NMR spectra, as well as elemental analysis. No polymer was obtained from the copolymerization of 2 and AN with or without AIBN initiator. Based on the structures of the products obtained from the copolymerization, a number of polymerization mechanisms are proposed. © 1996 John Wiley & Sons, Inc.     

Complex formation and degradation in poly(acrylonitrile‐co‐vinyl acetate) containing copper nitrate

The pyrolysis of polymers containing metal nitrates may provide a relatively simple, rapid, and advantageous method of producing high‐temperature superconductors (HTSCs). The advantage lies in the ability to use conventional polymer processing or microlithographic patterning before pyrolysis. A copolymer of acrylonitrile and vinyl acetate [P(AN‐VA)], a well‐known fiber‐forming polymer, was investigated as a potential HTSC precursor. Complex formation with the highly polar acrylonitrile groups was expected to enhance atomic‐level mixing and hinder nitrate recrystallization. The metal nitrates were found to have a profound effect on P(AN‐VA) pyrolysis. P(AN‐VA) containing copper nitrate (CuN) exhibited complex formation and an exothermic decomposition that began at about 170 °C (reaction 1‐CuN). Reaction 1‐CuN had a heat of about 3.5 kJ/g_NO3 and a mass loss of about 0.99 g/g_NO3. As reaction 1‐CuN also involved the nitrile groups, it disrupted the nitrile cyclization reaction at about 290 °C. For a P(AN‐VA)/CuN ratio of 2/1, there was no nitrile cyclization, and the thermooxidative degradation temperature was reduced by approximately 200 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1023–1032, 2004     

Use of a pentachlorophenol degrading bacterium to bioremediate highly contaminated soil

ASphingomonas species that mineralizes high concentrations of pentachlorophenol (PCP) was isolated from a PCP-contaminated EPA Superfund site. This bacterium, identified asSphingomonas sp. strain RA2, is able to degrade PCP at concentrations of up to 300 μg/mL in liquid culture. This organism was tested for its ability to degrade high concentrations of PCP in a soil that did not contain organisms capable of degrading high concentrations of PCP. When inoculated into contaminated soil,Sphingomonas sp. RA2 mineralized PCP at concentrations of 300, 600, 900, and 1200 μg PCP/g of soil, but was unable to mineralize 1500 μg PCP/g of soil. Only very minimal loss of PCP was seen in uninoculated soils. The results of this study demonstrate thatSphingomonas sp. RA2 may be a useful organism for remediation of sites contaminated with high concentrations of PCP.     

Preparation of monodisperse functional poly(styrene-co-acrylamidoxime) microsphere with chelating amidoxime group

Monodisperse poly(styrene-co-acrylonitrile) microspheres were prepared by dispersion copolymerization of styrene (St) and acrylonitrile (AN) in ethanol (EtOH)/isopropanol medium. 2,2′-Azobis(isobutyronitrile) (AIBN) and poly(acrylic acid) (PAA) were utilized as initiator and steric stabilizer, respectively. The effects of PAA stabilizer, AIBN initiator, St/AN monomer ratio, and EtOH solvent on particle size and size distribution were investigated systematically. AN is a co-monomer with desired nitrile group (–CN); the functional P(St-co-acrylamidoxime) microsphere with chelating amidoxime group (–C(NH₂)=NOH) was derived by amidoximizing the nitrile group with hydroxylamine. The percentage of chemical modification was calculated to be 51.2% in this study.     

N-[4-(磺酰胺)苯基]丙烯酰胺与丙烯腈、甲基丙烯酸甲酯共聚合的竞聚率

N-[4-(磺酰胺)苯基]丙烯酰胺(ASPAA)单体可以均聚或与其它单体共聚合成具有药理活性的聚合物，制成水溶性、毒副作用小、具有缓释作用的大分子药物．同时，由于磺酰胺基具有一定的碱溶性，ASPAA与丙烯酸酯类等单体的共聚物可用于制备可碱显影、显影宽容度和耐印力等性能良好的平印、计算机直接制版版材．有关ASPAA与其它单体共聚的竞聚率还鲜见报道．本文在合成ASPAA单体的基础上，对ASPAA／丙烯腈和ASPAA／甲基丙烯酸甲酯共聚的竞聚率进行了研究。     

丙烯腈和甲基丙烯酸酯基团转移共聚的竞聚率

丙烯腈和甲基丙烯酸酯基团转移共聚的竞聚率邹友思，郭金全，兰涛，戴李宗，潘容华（厦门大学化工系，厦门，３６１００５）关键词基团转移共聚．竞聚率．丙烯腈．甲基丙烯酸酯近年来对基团转移共聚竞聚率的研究较活跃［１～３］，一般认为甲基丙烯酸酯和丙烯酸酯两类单体...     

Photoinduced ATRP of acrylonitrile with aniline as photoinitiator

Photo-mediated atom transfer radical polymerization (ATRP) of acrylonitrile (AN) was carried out at 25°C in N,N-dimethyl formamide (DMF) with aniline as photoinitiator. Polyacrylonitrile (PAN) with predictable average molecular weight and narrow molecular weight distribution was synthesized with 2-Bromopropionitrile (BPN) as ATRP initiator and FeCl₃·6H₂O/Triphenylphosphine (PPh₃) as the catalyst. The obtained kinetics showed that the photoinduced Fe-mediated ATRP of AN provided a route to synthesize well defined PAN with narrow molecular weight distribution (M_w/M_n). The living character of photoinduced Fe-mediated ATRP of AN was verified by the linear increase of molecular weights with monomer conversion and the molecular weights are in good agreement with the theoretic values. In addition, the chain extension experiments were successfully conducted under the same conditions. The periodic light on-off process was investigated for the photoinduced Fe-mediated ATRP of AN. The obtained PAN was characterized by ¹H nuclear magnetic resonance and gel permeation chromatography. The brominated PAN was used to perform chain-extension with AN as macroinitiator in order to verify the living nature of photoinduced ATRP of AN-Br.     

Copolymerization of 2-methylene-4-phenyl-1,3-dioxolane with electrophilic vinyl monomers through zwitterionic mechanism

Spontaneous copolymerization of cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane ( I ) with common electrophilic vinyl monomers, such as methyl α-cyanoacrylate (MCA), acrylonitrile (AN), and methyl methacrylate (MMA) were investigated to further explore zwitterion polymerization method with cyclic ketene acetals. In the reaction of I with MCA and AN, spontaneous copolymerization took place at ambient temperature. The copolymers of I with MCA gave low molecular weight polymers, but copolymers obtained with I and AN were high molecular weight polymers. In the reaction of I and MMA, high molecular weight copolymer was obtained only at temperatures above 80°C. Thus, obtained polymers were not the alternating copolymers and possessed high I content in all the cases. From the above results, macrozwitterionic mechanism was suggested as discussed.     

Copper(0)‐mediated living radical polymerization of acrylonitrile at room temperature

The copper(0)‐catalyzed living radical polymerization of acrylonitrile (AN) was investigated using ethyl 2‐bromoisobutyrate as an initiator and 2,2′‐bipyridine as a ligand. The polymerization proceeded smoothly in dimethyl sulphoxide with higher than 90% conversion in 13 h at 25 °C. The polymerization kept the features of controlled radical polymerization. ¹H NMR spectra proved that the resultant polymer was end‐capped by ethyl 2‐bromoisobutyrate species. Such polymerization technique was also successfully introduced to conduct the copolymerization of styrene (St) and AN to obtain well‐controlled copolymers of St and AN at 25 °C, in which the monomer conversion of St could reach to higher than 90%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Biobased Polymers via Radical Homopolymerization and Copolymerization of a Series of Terpenoid-Derived Conjugated Dienes with exo-Methylene and 6-Membered Ring

A series of exo-methylene 6-membered ring conjugated dienes, which are directly or indirectly obtained from terpenoids, such as β-phellandrene, carvone, piperitone, and verbenone, were radically polymerized. Although their radical homopolymerizations were very slow, radical copolymerizations proceeded well with various common vinyl monomers, such as methyl acrylate (MA), acrylonitrile (AN), methyl methacrylate (MMA), and styrene (St), resulting in copolymers with comparable incorporation ratios of bio-based cyclic conjugated monomer units ranging from 40 to 60 mol% at a 1:1 feed ratio. The monomer reactivity ratios when using AN as a comonomer were close to 0, whereas those with St were approximately 0.5 to 1, indicating that these diene monomers can be considered electron-rich monomers. Reversible addition fragmentation chain-transfer (RAFT) copolymerizations with MA, AN, MMA, and St were all successful when using S-cumyl-S’-butyl trithiocarbonate (CBTC) as the RAFT agent resulting in copolymers with controlled molecular weights. The copolymers obtained with AN, MMA, or St showed glass transition temperatures (T_g) similar to those of common vinyl polymers (T_g ~ 100 °C), indicating that biobased cyclic structures were successfully incorporated into commodity polymers without losing good thermal properties.     

Cobalt-mediated radical polymerization of acrylonitrile: kinetics investigations and DFT calculations

The successful controlled homopolymerization of acrylonitrile (AN) by cobalt-mediated radical polymerization (CMRP) is reported for the first time. As a rule, initiation of the polymerization was carried out starting from a conventional azo-initiator (V-70) in the presence of bis(acetylacetonato)cobalt(II) ([Co(acac)(2)]) but also by using organocobalt(III) adducts. Molar concentration ratios of the reactants, the temperature, and the solvent were tuned, and the effect of these parameters on the course of the polymerization is discussed in detail. The best level of control was observed when the AN polymerization was initiated by an organocobalt(III) adduct at 0 degrees C in dimethyl sulfoxide. Under these conditions, poly(acrylonitrile) with a predictable molar mass and molar mass distribution as low as 1.1 was prepared. A combination of kinetic data, X-ray analyses, and DFT calculations were used to rationalize the results and to draw conclusions on the key role played by the solvent molecules in the process. These important mechanistic insights also permit an explanation of the unexpected "solvent effect" that allows the preparation of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) by CMRP.     

Withanolide A biogeneration in in vitro shoot cultures of ashwagandha (Withania somnifera DUNAL), a main medicinal plant in Ayurveda

Multiple shoot cultures of two experimental lines of Withania somnifera plants (RS-Selection-1 and RS-Selection-2) were established using nodal segments as explants. The hormonal combinations of benzyl adenine and kinetin not only influenced their morphogenetic response but also differentially modulated the level of biogeneration of withanolide A in the in vitro shoots of the two lines. Interestingly, withanolide-A, that was hardly detectable in the aerial parts of field-grown Withania somnifera (explant source), accumulated considerably in the in vitro shoot cultures of the plant. The productivity of withanolide A in the cultures varied considerably (ca. 10-fold, 0.014 to 0.14 mg per gram fresh weight) with the change in the hormone composition of the culture media as well as genotype used as source of the explant. The shoot culture of RS-Selection-1 raised at 1.00 ppm of BAP and 0.50 ppm of kinetin displayed the highest concentration of withanolide A in the green shoots of 0.238 g per 100 g dry weight tissue. This was a more analytical concentration keeping in view the isolation yields so far reported from the dried roots of the field-grown plant (ca. 0.015 g per 100 g dry weight), even if isolation losses are considered during purification. The enhanced de novo biogenesis of withanolide A in shoot cultures was corroborated with radiolabel incorporation studies using [2-(14)C] acetate as a precursor. Production of withaferin A was also found in the in vitro shoot cultures. As this compound is a predominant withanolide of native shoots as well and has been already reported to be accumulated in in vitro shoot cultures, its biogeneration observed in these shoot cultures is not discussed in detail.     

衣康酸对聚丙烯腈原丝结构和性能的影响

控制单体配比 ,采用丙烯腈 (AN)与衣康酸 (IA)自由基溶液共聚 ,以偶氮二异丁腈为引发剂在溶剂二甲基亚砜中合成了聚丙烯腈原丝纺丝溶液 ,并纺制了碳纤维前驱体聚丙烯腈原丝 .通过元素分析、IR、DSC、13 C NMR等手段 ,讨论了共聚单体IA对共聚反应及聚丙烯腈原丝结构和性能的影响 .共聚反应时 ,共聚单体IA的加入量控制在AN/IA =98/2 (W/W )较合适 .利用IR谱 ,可定量分析IA在共聚中的摩尔分数 .经13 C NMR分析 ,随着共聚单体IR在共聚物中的摩尔分数的增加 ,共聚物的全同规整度增加 ,达到一定值后又呈下降趋势 .共聚单体IA能在较低温度时引发聚丙烯腈原丝的氧化、环化放热反应 ,且能减缓放热效应 .     

丙烯腈──苯乙烯/聚丙烯接枝共聚合

丙烯腈（AN）—苯乙烯（St）与聚丙烯（PP）非均相接枝共聚，得杨梅形树脂。研究了AN／St摩尔比对接枝聚合的影响，发现苯乙烯相对含量增大时，非接枝物产量增加，接枝率和接枝效率相应下降。从接枝物的C、H、N分析可计算出聚丙烯、丙烯腈和苯乙烯的组成比例。此外，用二乙烯基苯（DVB）作交联剂，制备了PP－g－（AN－co－St－co－DVB）接枝共聚物—交联型薄壳树脂，交联剂的存在使单体转化率和接枝效率高达100％。     

Effect of Solvent on the Radical Copolymerizability of Styrene with Acrylonitrile

Radical copolymerization of styrene (St, M₁) with acrylonitrile (AN, M₂) has been carried out using azobisisobutylonitrile as an initiator in benzene, dimethylsulfoxide, acetonitrile, and ethanol at 60 and 80°C. Good linear correlationships were obtained by plotting the values of log r₁, log r₂, Q₂, and e₂ against those of vC[dbnd]N and vC[dbnd]C determined in the solvents: the increase in the interaction between AN and the solvent was found to decrease the values of log r₁ and e₂ but to increase those of log r₂ and Q₂. The results are discussed in terms of the solvation both in the ground state and in the transition state.