Terpolymerization of acrylamide,acrylic acid,and acrylonitrile: Synthesis and properties

Free-radical solution terpolymerization of acrylamide, acrylic acid, and acrylonitrile was carried out in a mixture of dimethylformamide and water (60 : 40,v/v) at 85°C using benzoyl peroxide as the initiator. The polymers were characterized by elemental analysis, IR, ¹H-NMR, TGA, and viscosity measurements. Elemental analysis data were used to evaluate the terpolymer composition. The reactivity ratios were determined by Fineman–Ross and Kelen–Tudos methods. The reactivity ratios (r) for the copolymerization of (1) acrylic acid + acrylonitrile with (2) acrylamide was found to be r₁ = 0.86 ± 0.09 and r₂ = 1.93 ± 0.03, respectively, by the Kelen–Tudos method. The Fineman–Ross method yielded a value of r₁ = 0.86 ± 0.05 and r₂ = 1.94 ± 0.09, respectively. The activation energy values for various stages of decomposition were calculated from TGA analysis. Voluminosity (V_E) and the shape factor (ν) were also computed from the viscosity measurements in different ratios of the solvent mixture. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 217–228, 1998     

Preparation and characterization of biocompatible poly(L‐lactic acid)/gelatin blend membrane

Poly(L ‐lactic acid) (PLLA)/gelatin blend membranes were prepared by solution casting method and using dimethyl sulfoxide (DMSO) as a cosolvent. Scanning electron microscopy measurement indicated that when the amounts of gelatin in PLLA/gelatin blend membranes are less than 5%, the sizes of phase separation of gelatin are in range of several hundred nanometers. These benefit in retaining the strength of PLLA membranes. X‐ray diffraction analysis revealed that the semicrystalline PLLA became amorphous and the melt temperature of crystalline PLLA changes from 56 to 38°C after it was processed in DMSO solvent. When the content of gelatin is less than 5%, the films not only retain a good mechanical property but also improve the hydrophilicity of PLLA. The molecular motion of PLLA in blend films were also investigated by solid state ¹³C CP/MAS NMR. On the basis of the result of relaxation times, it was found that the molecular motion of PLLA100 and PLLA/gelatin blends increased when compared with that of original PLLA. It was further verified that semicrystalline PLLA became amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 269–276, 2006     

聚二烯丙基二甲基氯化铵-丙烯酰胺-丙烯酸的制备与表征

以丙烯酸(AA)、丙烯酰胺(AM)用量和体系pH等作为考察因素,以聚合物配合质量分数为2%铬粉应用于皮革鞣制工艺的应用效果为指标,对聚二烯丙基二甲基氯化铵-丙烯酰胺-丙烯酸(PDM-AM-AA)的制备条件进行了优化.结果表明:当n(DM):n(AM):n(AA)=1:2:3,体系pH=5.5时,聚合物产率达94.53%,配合质量分数为2%铬粉应用于皮革鞣制工艺效果较好.对所制备产物的结构采用红外光谱、X射线衍射和差示扫描量热进行了表征,表征结果表明三种单体成功发生了聚合.     

Preparation of a kaolinite–poly(acrylic acid acrylamide) water superabsorbent by photopolymerization

A novel kaolinite–poly(acrylic acid acrylamide) water superabsorbent with a water absorbency and salt solution absorbency of 433 and 108 g/g, respectively, was successfully synthesized by the photopolymerization of acrylic acid with acrylamide in the presence of kaolinite powder under 30 min of ultraviolet irradiation at room temperature. The results showed a synergetic effect of the mixed photoinitiators (Michler's ketone and benzophenone) on the water absorbency, and the incorporation of less than 10 wt % kaolinite into the water superabsorbent slightly improved the water absorbency and salt solution absorbency and obviously upgraded the water retention, as demonstrated by retention testing as well as thermogravimetric analysis and differential scanning calorimetry. Fourier transform infrared spectroscopy verified the structure of the kaolinite composite superabsorbent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2875–2881, 2006     

Radiation‐induced graft copolymerization of acrylic acid/acrylonitrile onto LDPE and PET films and its biodegradability

Graft copolymerization of acrylic acid/acrylonitrile (AAc/AN) comonomer onto low‐density poly(ethylene) (LDPE) and poly(ethylene terephthalate) (PET) films using direct radiation grafting technique has been investigated. The effect of different reaction conditions on the grafting yield was studied. The structure of the grafted films at different compositions was characterized by FTIR, TGA, SEM, and XRD. Biodegradation of grafted LDPE and PET was investigated by burial method in two types of Egyptian soils (agricultural and desert soils). The bacteria responsible for biodegradation were isolated and characterized, and the capacities for the growth on these polymers as substrates were compared. The isolates from agricultural soil were characterized as Pseudomonas, Alcaligenes, Bacillus, Proteus, and Enterobacter, whereas the isolates from desert soil were characterized as Alcaligenes, Bacillus, and Pseudomonas. The highest degradation rate was found to be achieved using agricultural soil. It is found that the isolated strains belonging to the genus Pseudomonas were mainly responsible for the degradation of both polymers. It has also been found that the increase of AAc ratio in the composition increases the hydrophilicity of the films and the degradation rate. PET polymer is generally found to be more resistant to the biodegradation than LDPE in the two types of soils tested. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

4‐Acetamidophenyl acrylate copolymers with acrylonitrile and N‐vinyl‐2‐pyrrolidone: Synthesis,characterization, and reactivity ratios

4‐Acetamidophenyl acrylate (APA) was synthesized and characterized by IR, ¹H and ¹³C NMR spectroscopies. Homo‐ and copolymers of APA with acrylonitrile (AN) and N‐vinyl‐2‐pyrrolidone (NVP) were prepared by a free radical polymerization. All the copolymer compositions have been determined by ¹H NMR technique, and the reactivity ratios of the monomer pairs have been evaluated using the linearization methods Fineman–Ross, Kelen–Tudos, and extended Kelen–Tudos. Nonlinear error‐in‐variable model (EVM) method was used to compare the reactivity ratios. The reactivity ratios for copoly(APA–AN) system were APA(r₁) = 0.70 and AN(r₂) = 0.333, and for copoly(APA–NVP) system the values were APA(r₁) = 4.99 and NVP(r₂) = 0.019. Thermal stability and molecular weights of the copolymers are reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1919–1927, 2006     

Fabrication and characterization of centrifugally spun poly(acrylic acid) nanofibers

The production of poly(acrylic acid) (PAA) nanofibers by the centrifugal spinning of PAA solutions in water is reported. The effect of the spinneret rotational speed and concentration of PAA solutions on the diameter of nanofibers and on their quality (assessed by the absence of beads) is discussed. The main physical properties of PAA such as glass-transition temperature (T_g) are studied in detail and compared to the feature of the as-received homopolymer. It is shown that the glass-transition temperature of the bulk PAA and PAA nanofibers (as measured by differential scanning calorimetry) depends on the heating rate according to a Williams–Landel–Ferry-like equation. Raman spectroscopy data provided additional information about the differences between the as-received polymer and the nanofibers. Preliminary results on antibacterial properties of the PAA nanofibers are reported. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47480.     

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate: Synthesis and characterization

Dispersion copolymerization of acrylamide with acrylic acid in an aqueous solution of ammonium sulfate using poly(2‐acrylamido‐2‐methylpropanesulfonic acid sodium) as the stabilizer and ammonium persulfate (APS) as the initiator was investigated. The influence of initiator concentration, stabilizer concentration, ammonium sulfate concentration, chain‐transfer agent concentration, and polymerization temperature on the copolymerization was discussed. The results showed that varying the ammonium sulfate concentration could affect the particle size and the intrinsic viscosity of the copolymer significantly. With increasing the stabilizer concentration, the particle size of the copolymer decreased first, and then increased, meanwhile the intrinsic viscosity of the copolymer decreased. The increase of initiator concentration, chain‐transfer agent concentration, and polymerization temperature resulted in the increase in the particle size. Polydisperse spherical particles were formed in the system, and the kinetics for the dispersion copolymerization were discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3685–3690, 2006     

A review of biodegradable polymers: uses,current developments in the synthesis and characterization of biodegradable polyesters,blends of biodegradable polymers and recent advances in biodegradation studies

This review considers the uses of biodegradable polymers in terms of their relevance within current plastic waste management of packaging materials, biomedical applications and other uses; research papers and patents are catalogued. The chemical synthesis of polyesters and the microbial production of poly(hydroxyalkanoate)s, including recent publications in these areas, are covered and methods of characterization and structural analysis are outlined. Current research into two- and three-component blends is reviewed as a method of reducing overall costs and modifying both properties and biodegradation rates of materials. Finally, there is a summary of degradation processes. Both abiotic and biotic reactions are discussed, together with the development of biodegradation test methods, particularly with respect to composting. © 1998 Society of Chemical Industry     

One‐ and two‐dimensional nuclear magnetic resonance studies on the compositional sequence and the microstructure of acrylamide/acrylonitrile copolymers

Copolymers containing acrylamide (A) and acrylonitrile (B) units of different compositions were synthesized by free‐radical solution polymerization. The reactivity ratios were estimated by the Kelen Tudos and nonlinear error‐in‐variable methods. The triad sequence distribution in terms of A‐ and B‐centered triads were obtained from ¹³C{¹H}‐NMR spectroscopy. The complete spectral assignments in terms of compositional and configurational sequences of the overlapping carbon and proton spectra of these copolymers were done using distortionless enhancement by polarization transfer (DEPT), two‐dimensional proton‐detected heteronuclear correlation (inverse‐HETCOR), and total correlated spectroscopy (TOCSY) experiments. The Monte Carlo simulation was used to study the effect of the fractional conversion on the triad fractions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 55–67, 1999     

Synthesis and characterization of lactose based resorcinol resin

Resorcinol‐lactose resin was synthesized using phosphoric acid as the catalyst at 95°C. ¹³C‐NMR measurements proved that the chemical reaction is initiated at the 4‐ or 6‐carbon position in benzene ring. Sample separation by size‐exclusion chromatography (SEC) technology indicated that the resin consists of reacting mixtures of oligomer of lactose, glucose, and galacose with resorcinol. The resin, using a by product of diary industry as a main component, could be potentially applied as a novel adhesive to the wood process industry. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2581–2585, 2002     

聚天冬氨酸的生物降解性能及降解机理研究

应用摇床实验法对所合成的聚天冬氨酸(PASP)的生物降解性能进行了系统研究,分析讨论了PASP浓度、分子量以及合成原料与其生物降解性能的关系。对分子量为5 400左右的PASP来说,当接种物浓度为10 mg/L,其浓度低于50 mg/L时,第4 d降解率就达到100%;但对接种物浓度为1 001.30 mg/L的试液来说,分子量为9 700左右的PASP的生物降解性能最好,第4 d降解率可达到82.1%;以铵盐B为原料的PASP生物降解性能最佳,在第20 d,降解率就达到100%;同时,对实验试液的氨氮值进行了测定,降解后试液的氨氮值均达到直接排放的要求标准。利用红外光谱对PASP进行了结构表征,并进一步探讨了PASP的生物降解机理,认为PASP的生物降解是生物物理降解与生物化学降解协同作用的结果。     

烟煤和白煤结构表征及煤净洁添加剂的研制

运用远红外傅立叶变换光谱、超导核磁、光栅发射光谱、元素分析、X射线荧光光谱等分析测试手段,对烟煤和白煤的基本结构单元进行了表征。研究表明,白煤骨架中的芳环聚合度比烟煤大,碳支链较烟煤少;而且在白煤骨架中部分三维碳骨架中可能存在C—O—Si—O—C化学键。研制出了型煤净洁剂,将其与白煤粉、烟煤粉进行拌合,冷压后制成的型煤着火点降低,燃烧速度加快,不仅燃煤效率提高了20%,而且消烟除尘效果已达排放标准,有害气体二氧化硫降低了48%。     

Characterization of compositional heterogeneity in the polyethylene prepared with bis(imino)pyridyl iron(II) precatalyst and triethylaluminum

Analytical tools including solvent gradient elution fractionation (SGEF), GPC, ¹³C NMR, and differential scanning calorimetry (DSC) are integrated for the characterization of compositional heterogeneity in the polyethylene (PE) prepared with the LFeCl₂/AlEt₃ catalytic system. The results indicate that at least two different kinds of catalytic species are present in ethylene polymerization. One active species generating branched PE gives low molecular weight; another kind of active species gives high molecular weight PE with high linear structure. The amount of branch decreases with increasing the molecular weights, and the small proportion of the branched PE shows low molecular weight with vinyl‐terminated end group, indicating that the branched PE is generated from the catalytic species giving low activity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of N,N'-diallylmalonamide and its copolymer gels with acrylic acid and acrylamide

N,N'-diallylmalonamide (DAM) has been prepared via classical aminolysis of diethyl malonate with allylamine. Its structure was confirmed by elementary microanalysis as well as ¹H NMR and FT-IR spectroscopy. The new diallyl monomer is water-soluble and able to copolymerize radically with water-soluble monomers, such as acrylamide and acrylic acid, to give transparent hydrogels by using K₂S₂O₈ as initiator. Homopolymerization of DAM yields clear hydrogels with high swelling ability.     

Synthesis,characterization and biodegradation studies of chain‐coupled polyesters based on tartaric acid

A series of chain‐coupled polyesters based on tartaric acid was synthesized and characterized following a two‐step procedure. In the first step, tartaric acid based hydroxyl terminated polyesters with various alkane diols were prepared and then, in a second step, a chain‐coupling approach using hexamethylene diisocyanate was employed on the synthesized polyesters to prepare a series of chain‐coupled polyesters. The number‐average molecular weights (M_n) of the polyesters were found to vary in the range (4.8 ? 28.1) × 10³ g mol^?1. Thermomechanical studies demonstrate that the storage modulus of the chain‐coupled polyesters decreases with increasing polymethylene chain length which is attributable to enhanced flexibility. The isolation of bacteria on medium containing polymer as the sole source of carbon indicates the ability of the synthesized polyesters to be taken up by microorganisms for growth. © 2013 Society of Chemical Industry     

The isolation and characterization of lignin of kenaf fiber

In this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. The C₉ formula is calculated for kenaf fiber MWL as C₉H_9.32O_3.69(OCH₃)_1.30. The spectra of FTIR, ¹H‐NMR, and ¹³C‐NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.14 and 1.31, respectively, per C₉ unit. The OH_aliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OH_ph is 9.7%. It is evident that the β‐O‐4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in β‐O‐4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Heterogeneous structure of poly(glycolic acid) fiber studied with differential scanning calorimeter, X-ray diffraction, solid-state NMR and molecular dynamic simulation

The heterogeneous structures of poly(glycolic acid) (PGA) fibers which have been used as bio-degradable suture were studied by differential scanning calorimeter (DSC),X-ray diffraction and ¹³C solid state NMR. The ¹³C cross polarization NMR spectra without magic angle spinning of the stretched fibers observed by changing the angle between the fiber axis and the magnetic field clearly showed the heterogeneous structures which consist of three components; well-oriented, poorly-oriented and isotropic amorphous components. The local structure, distribution of the fiber axis and fraction of each component were determined quantitatively. Change in the heterogeneous structure by changing the stretching method in the sample preparation and by changing the stretching ratio was also monitored. The X-ray diffraction data of the fibers are in good agreement with the ¹³C CP NMR data. Change in the heterogeneous structures correlate with change in the thermal properties observed by DSC method. The molecular dynamic simulation showed the generation of trans conformation of PGA chain and also change in the fraction of other conformations by stretching, which supports the experimental results obtained above and gives additional structural information.     

Sonochemical polymerization of acrylic acid and acrylamide in the presence of a new redox system— A comparative study

Acrylic acid and acrylamide were polymerized by a peroxydisulfate–suberic acid redox system under a nitrogen atmosphere both in the presence and in the absence of ultrasound (at constant frequency). The rate of polymerization was determined for different concentrations of monomer, initiator, and activator and for different percentages of ultrasonic intensity. The polymers were characterized by X‐ray diffraction and ¹H‐NMR spectroscopy. A probable mechanism is proposed to explain the experimental results obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3685–3692, 2003