Solid‐state grafting of succinic anhydride onto poly(vinyl alcohol)

The graft reaction of succinic anhydride onto poly(vinyl alcohol) (PVA) was catalyzed by p‐toluenesulfonic acid monohydrate in solid state. The infrared spectra and ¹H‐NMR spectra confirmed that succinic anhydride was successfully grafted onto PVA backbone. The influences of reaction temperature, reaction time, the amount of succinic anhydride, and the amount of catalyst on the graft reaction were studied. Uncrosslinked PVA graft copolymer with grafting degree up to about 6.5% could be obtained under low reaction temperature, short reaction time, and low amount of catalyst, whereas crosslinked PVA with high gel content could be obtained under high reaction temperature, long reaction time, and high amount of catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 848–852, 2007     

Wood preservation by a mixed anhydride treatment: A 13C‐NMR investigation of simple models of polymeric wood constituents

The treatment of wood by a mixed aceto/oleic (or other fatty acid residue) anhydride promoted as a safe and environmentally friendly wood preservation system was examined quantitatively by liquid‐phase ¹³C‐NMR and solid‐phase magic angle spinning–DEC (proton decoupling) ¹³C‐NMR through of all its different stages to determine which reactions occurred with simple model compounds of the polymeric constituents of wood. The preparation of the mixed aceto/oleic anhydride under different conditions was also undertaken. The anhydride formed, but its percentage yield was only 30%. The mix composed of unreacted acetic anhydride, the mixed aceto/oleic anhydride, and a large proportion of free acetic and oleic acid, which are used for wood preservation, yielded the acetylation of the lignin model compound (1) by the reaction of the acetic anhydride with it and (2) by the reaction of the acetic part of the mixed anhydride. In this reaction, all of the mixed anhydride was consumed. The oleic part of the mixed anhydride was unable to form esters with either lignin or wood holocellulose as it was far less reactive than the acetic part. Some acetylation of holocellulose occurred, and some traces of its oleic acid ester also occurred under some conditions. This system of treatment through a mixed anhydride appeared to consist of just an acetylation with acetic anhydride mixed with some oleic acid as a water repellent, both of which are already known processes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and thermal properties of tris (3‐aminophenyl) phosphine oxide‐based nadimide resins

This article describes the synthesis, characterization, and thermal properties of nadimides obtained by reacting endo‐5‐norbornene‐2,3‐dicarboxylic acid anhydride (nadic anhydride) (NA), 4,4′‐oxodiphthalic anhydride (ODA), 1,4,5,8‐naphthalene tetra carboxylic dianhydride (NTDA) in glacial acetic acid/DMF. Structural characterization of the resins was done by elemental analysis, IR, ¹H‐NMR, and ¹³C‐NMR. The DSC scan showed the endothermic transition in the temperature range of 120–270°C. Multistep decomposition was observed in the TG scan of uncured resins in nitrogen atmosphere. Isothermal curing of the resins was done at 250 and 300°C for 1 h in an air atmosphere. These cured resins were stable to (350 ± 30)°C and decomposed in a single step above this temperature. This may be due to the retro Diels Alder (RDA) reaction. The char yield of the resins increased significantly on curing. The char yield was highest for P‐2N resin and this could be due to the presence of rigid skeleton i.e. naphthalene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n‐octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity

The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n‐octyl)ammonium chloride (N₂₂₂₈Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal mol^?1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N₂₂₂₈Cl + MS) differ only by 0.8 kcal mol^?1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this “leveling‐off” of the dependence DS on the polarity of the parent MS employed. N₂₂₂₈Cl recovery and recycling is feasible.     

New unsaturated derivatives of Xanthan gum: Synthesis and characterization

Unsaturated Xanthan derivatives, which can be used for the development of biodegradable three-dimensional networks having hydrogel properties, were prepared by esterification under various conditions. Xanthan gum derivatives with different degrees of substitution were obtained by reaction with an unsaturated organic acid (acrylic acid) or with acid reactive derivatives (acryloyl chloride, maleic anhydride). The presence of acrylate and maleate groups in the modified structure of Xanthan gum was detected by ATR-FTIR, ¹H liquid NMR and ¹H HRMAS NMR spectroscopies. The degree of substitution as determined by ¹H NMR could be controlled by varying the chemical nature of functionalisation agent, reaction time and temperature.The results proved that this polysaccharide can be modified by esterification with acids or unsaturated acid derivatives for further synthesis of hydrogels. Maleic anhydride presents a higher reactivity as compared to acrylic acid and acryloyl chloride.     

Synthesis and characterization of the new unsaturated epoxyoligoester suitable for further modification

In this article, the synthesis and characterization of the new unsaturated epoxyoligoester suitable for further modification have been presented. The new unsaturated epoxyoligoester was prepared by the chemical modification of the structure of the unsaturated oligoester obtained in polycondensation process of cyclohex‐4‐ene‐1,2‐dicarboxylic anhydride, maleic anhydride, and ethylene glycol. The chemical modification of the structure of initial oligoester by 38–40% peracetic acid in mild conditions allowed to introduce the oxirane groups into the oligoester backbone. The structure of the samples before and after epoxidation was characterized by FTIR, ¹H NMR, DSC, and elemental analyses. The FTIR and ¹H NMR analyses confirmed that the oxidation reaction took place through the double bonds in cyclohexenyl rings, whereas the double bonds in the unsaturated chain remained unaltered. Moreover, the epoxidation reaction was performed at 20 and 40°C for 1–6 h to define the optimum temperature and time conditions of this process. The optimum temperature and time conditions were 40°C and 2.5 h, respectively. In this conditions, the maximum conversion of the double bonds (98.3%) and minimal epoxide degradation were observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Development of linseed oil based polyesteramide without organic solvent at lower temperature

Linseed oil based polyesteramide was synthesized at lower temperature in the absence of organic solvent through condensation polymerization reaction [Sf‐LPEA]. In this reaction N,N‐bis(2‐hydroxyethyl) linseed oil fatty amide and phthalic anhydride were heated at temperature lower than their onset of melting points and the by‐product, such as water was removed by application of vacuum technique. This approach was employed to overcome the use of volatile organic solvents used during processing and application of resin, which are ecologically harmful. The solubility of Sf‐LPEA was checked in different polar and nonpolar solvents. The FTIR, ¹H NMR, and ¹³C NMR spectral techniques were used to confirm the structure of Sf‐LPEA. The physicochemical, physicomechanical, and chemical resistance properties of the resin were investigated by standard methods. DSC and TGA were used to determine, respectively, the curing behavior and thermal stability of the resin. The comparative study of these properties of Sf‐LPEA with reported polyesteramide [LPEA], which are normally synthesized at higher temperature in organic solvent, was done. It was found that Sf‐LPEA exhibited improved physicomechanical, chemical resistance properties, and higher thermal stability compared with LPEA, and hence can find application as corrosion protective coating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1143–1148, 2007     

Graft copolymerization of maleic anhydride onto low‐molecular‐weight polyisobutylene through solvothermal method

The free‐radical graft copolymerization of maleic anhydride (MAH) onto highly reactive low molecular weight polyisobutylene was conducted by the use of benzoyl peroxide as an initiator through the solvothermal method. Fourier transform infrared spectra and ¹H‐NMR spectra confirmed that maleic anhydride was successfully grafted onto highly reactive low molecular weight polyisobutylene backbone, and the grafting mechanism also was proposed. The effect of benzoyl peroxide content, MAH concentration, total reactant amount in the reaction vessels, reaction temperature and time, and different kinds and volumes of solvents on MAH's degree of grafting was investigated in detail. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of new poly(amide–imide)s with chiral architectures via direct polyamidation reaction

N‐trimellitylimido‐L ‐methionine ( 3 ) was prepared by reaction of trimellitic anhydride ( 1 ) with ‐L ‐methionine ( 2 ) in acetic acid solution at refluxing temperature. This diacid was reacted with thionyl chloride, and N‐trimellitylimido‐L ‐methionine diacid chloride ( 4 ) was obtained in quantitative yield. The resulting diacid chloride was reacted with p‐aminobenzoic acid in dry acetone and bis(p‐aminobenzoic acid)‐N‐trimellitylimido‐L ‐methionine ( 5 ) was obtained as a novel optically active amide–imide diacid monomer in high yield. The direct polycondensation of amide–imide diacid monomer 5 with several aromatic diamines was carried out with tosyl chloride (TsCl)/pyridine (Py)/dimetheylformamide (DMF) system. The resulting thermally stable poly(amide–imide)s (PAIs) were obtained in good yields and inherent viscosities ranging between 0.24 and 0.46 dL g^?1 and were characterized with FTIR, ¹H NMR, CHN, and TGA techniques. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1248–1254, 2007     

Production of alkenyl succinic anhydrides from low‐erucic and low‐linolenic rapeseed oil methyl esters

Fatty acid methyl esters from low‐erucic and low‐linolenic rapeseed oil were used to produce alkenyl succinic anhydrides. A second‐order Doehlert uniform network design was used to investigate the influence of the reaction temperature and the molar ratio between the maleic anhydride and the main unsaturated rapeseed oil methyl esters on the yield of alkenyl succinic anhydride from methyl oleate. Further subjects of investigation were the conversion of methyl oleate, the formation of side reaction products, the Gardner color of the product and its viscosity, and finally the content of maleic anhydride remaining in the medium after the reaction. Alkenyl succinic anhydride from methyl oleate was isolated by column chromatography and analyzed by IR, ¹H‐ and ¹³C‐NMR and MS. The optimal reaction conditions for obtaining the maximum yield of alkenyl succinic anhydride from methyl oleate in the experimental domain (80%) were 210‐220 °C and a maleic anhydride/rapeseed oil methyl ester molar ratio of 1.5. However, the products synthesized in these conditions showed a high degree of viscosity (0.45 kg m^?1 s^?1), a very dark color (18 Gardner color) and a high content of undesirable side products (6%), which could hinder their industrial use. A molar ratio of less than 1.5 led to a clearer and less viscous product, although with a lower alkenyl succinic anhydride content.     

Cationic cyclization of purified natural rubber in latex form with a trimethylsilyl triflate as a novel catalyst

Cyclization of deproteinized natural rubber (DPNR) or purified natural rubber latex was effectively performed in latex phase by using trimethylsilyl‐trifluoromethane sulfonate or trimethylsilyl triflate (TMSOTF) as a novel catalyst, which is still not reported in the case of natural rubber latex. Various cyclization conditions affecting the degree of cyclization were studied, such as dry rubber contents, temperature, TMSOTF concentrations, and time. The cyclized products were characterized by FTIR, Raman, ¹H‐, and ¹³C‐NMR spectroscopies, as well as DSC and TGA. The degree of cyclization was estimated by ¹H‐NMR spectrum. It was found that the degree of cyclization in NR was a function of cyclization conditions. The thermal stability of cyclized DPNR increased with the degree of cyclization. Solubility of the obtained rubber was good in chloroform, toluene, cyclohexanone, and cyclohexane, and bad in tetrahydrofuran. The average number molecular weight of cyclized DPNR with 76% degree of cyclization was about 4.2 × 10⁴ g/mol. On the basis of FTIR, Raman, ¹H‐, and ¹³C‐NMR, the C?C of cyclized DPNR dramatically decreased after prolonged reaction time. In addition, the topology of cyclization DPNR particles was rough on its rubber particle as analyzed by TEM. The mechanism for this reaction will also be discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007.     

Synthesis,characterization and thermal degradation of poly[2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate]

In this work, 2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate (BPHEMA) [monomer] was synthesized by the addition of methacrylic acid to 1‐epoxyethyl‐3‐bromophenyl‐3‐methyl cyclobutane. The monomer and poly(BPHEMA) were characterized by FT‐IR and [¹H] and [¹³C]NMR. Average molecular weight, glass transition temperature, solubility parameter, and density of the polymer were also determined. Thermal degradation of poly[BPHEMA] was studied by thermogravimetry (TG), FT‐IR. Programmed heating was carried out at 10 °C min⁻¹ from room temperature to 500 °C. The partially degraded polymer was examined by FT‐IR spectroscopy. The degradation products were identified by using FT‐IR, [¹H] and [¹³C]NMR and GC‐MS techniques. Depolymerization is the main reaction in thermal degradation of the polymer up to about 300 °C. Percentage of the monomer in CRF (Cold Ring Fraction) was estimated at 33% in the peak area of the GC curve. Intramolecular cyclization and cyclic anhydride type structures were observed at temperatures above 300 °C. The liquid products of the degradation, formation of anhydride ring structures and mechanism of degradation are discussed. © 1999 Society of Chemical Industry     

Supercritical fluid process for the synthesis of maleated poly(vinylidene fluoride)

Poly(vinylidene fluoride) was grafted with maleic anhydride monomer via a free‐radical mechanism in supercritical carbon dioxide medium. The free‐radical initiator chosen for this study was benzoyl peroxide. The structure of the resultant copolymer pendant groups was determined by ¹H NMR spectroscopy to consist of individual succinyl anhydride functional groups. The degree of functionalization (graft level) was obtained by FTIR spectroscopy through the correlation of absorbance bands using standard samples. The FTIR analysis indicated increased graft level with monomer loading, reaction temperature, and treatment time; however, initiator loading and reaction temperature showed more‐complex behavior. Graft levels increased at moderate benzoyl peroxide initiator loadings (5.0 wt%) and decreased at the highest initiator loadings (10.0 wt%). POLYM. ENG. SCI., 45:631–639, 2005. © 2005 Society of Plastics Engineers     

Phosphorus‐containing epoxy resins: Thermal characterization

Three novel aromatic phosphorylated diamines, i.e., bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl} pyromellitamic acid (AP), 4,4′‐oxo bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AB) and 4,4′‐hexafluoroisopropylidene‐bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AF) were synthesized and characterized. These amines were prepared by solution condensation reaction of bis(3‐aminophenyl)methyl phosphine oxide (BAP) with 1,2,4,5‐benzenetetracarboxylic acid anhydride (P)/3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride (B)/4,4′‐(hexafluoroisopropylidene)diphthalic acid anhydride (F), respectively. The structural characterization of amines was done by elemental analysis, DSC, TGA, ¹H‐NMR, ¹³C‐NMR and FTIR. Amine equivalent weight was determined by the acetylation method. Curing of DGEBA in the presence of phosphorylated amines was studied by DSC and curing exotherm was in the temperature range of 195–267°C, whereas with conventional amine 4,4′‐diamino diphenyl sulphone (D) a broad exotherm in temperature range of 180–310°C was observed. Curing of DGEBA with a mixture of phosphorylated amines and D, resulted in a decrease in characteristic curing temperatures. The effect of phosphorus content on the char residue and thermal stability of epoxy resin cured isothermally in the presence of these amines was evaluated in nitrogen atmosphere. Char residue increased significantly with an increase in the phosphorus content of epoxy network. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2235–2242, 2002     

N-乙酰-L-谷氨酸的制备

以 L-谷氨酸为原料 ,在碱性条件下用乙酸酐作为乙酰化试剂一步合成 N -乙酰 -L-谷氨酸的新工艺。获得最佳反应条件为 :L-谷氨酸与乙酸酐的摩尔比为 1 .0∶ 1 .3 ,酰化试剂分 3次加入 ;反应 p H值为 8～ 1 0之间 ;反应温度控制在 0～ 5°C;酸化结晶 p H值为 1 .0～ 2 .0 ;反应时间 1～ 3h。产品收率为 72 .0 %。     

Characterization of morphology in chemically modified styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene by solid‐state nuclear magnetic resonance

Multiphase triblock styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) copolymers chemically modified with maleic anhydride (MAH) in the presence of a radical initiator by reactive extrusion were studied by solid‐state ¹H‐NMR and ¹³C‐NMR. In the experiments performed, the concentrations of MAH and initiator were kept constant, whereas the temperature profile in the extruder was varied. Samples with known extents of grafting and crosslinking were analyzed with NMR with techniques based on proton spin diffusion to investigate the microphase structure of the modified copolymers. The ¹³C‐NMR results show that the size of the rigid domains was about 15 nm and was not significantly changed by the modification. Alterations in the rubbery phase were illustrated by measured changes in proton spin‐spin (T₂) relaxation times. The fraction of protons having intermediate mobilities increased slightly in modified SEBS with respect to that observed in unmodified copolymers. These results were found to be independent of the extruder temperature profiles used, at least in the range studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of vinyl substitute poly(silphenylene‐siloxane) via silyl hydride‐dialkoxysilane process

The synthesis of vinyl‐substituted silphenylene‐siloxane polymer through B(C₆F₅)₃ catalyzed polycondensation of 1,4‐bis(dimethylsilyl)benzene and vinylmethyldimethoxysilane is described. ¹H‐NMR, ²⁹Si‐NMR, and UV spectroscopy indicate that the vinyl groups remain undamaged during the polycondensation reaction. No hydrosilylation side reaction is observed under the reaction conditions. The microstructure of the polymer is not perfectly alternating with a randomization of 20%. The temperature for 5% mass loss is 430°C in inert atmosphere and 417°C in oxidative atmosphere with a residue of 56% at 700°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Succinoylation of wheat straw hemicelluloses in N,N‐dimethylformamide/lithium chloride systems

The chemical modification of native wheat straw hemicelluloses with succinic anhydride using N,N‐dimethylformamide/lithium chloride system as solvent and pyridine and/or 4‐dimethyaminopyridine as catalyst has been examined. In particular, the progress of the succinoylation reaction is studied as a function of the molar ratio of succinic anhydride/anhydroxylose unit in native hemicelluloses from 1:1 to 5:1, DMAP concentration 0.025–0.20 g, reaction temperature 40–140 °C, and reaction time 2–12 h with succinic anhydride. The degree of substitution of succinylated hemicelluloses ranges between 0.4 and 1.5 depending on the experimental conditions. FTIR and ¹H NMR spectroscopic characterization of the esterified polymers indicates a monoester substitution. The thermal stability of the esterified polymer decreases slightly upon chemical modification, but no significant further decrease in thermal stability is observed for DS ≥ 0.7. © 2001 Society of Chemical Industry     

Synthesis and Characterization of a Novel Low‐Viscosity Unsaturated Hyperbranched Polyester Resin

Hyperbranched thermosetting resin is the best additive for toughening and reinforcing linear thermosetting resin. A novel low‐viscosity unsaturated hyperbranched polyester resin (UHPR) is synthesized by the reaction between maleic anhydride monoisooctyl alcohol ester and a hydroxyl‐ended hyperbranched polyester resin (HPR) prepared from phthalic anhydride (PA) and trimethylolpropane (TMP). The structure of HPR is characterized by FT‐IR and ¹H NMR, and its degree of branching is deduced by comparing with the ¹H NMR spectrum of a model compound. The molecular weights of HPR and UHPR are determined by theoretical calculation and MALDI‐TOF MS measurements. This low‐viscosity (< 10 000 cP) novel UHPR can be applied in the field of environment‐friendly coatings and in toughening and reinforcing linear unsaturated polymers.     

Ring‐opening polymerization of trimethylenecarbonate and its copolymerization with ϵ‐caprolactone by lanthanide (II) aryloxide complexes

Lanthanide metal (II) 2,6‐di‐tert‐butylphenoxide complexes (ArO)₂Ln(THF)₃ (Ln = Sm 1 , Yb 2 ) alone have been developed to catalyze the ring‐opening polymerization of trimethylenecarbonate (TMC) and random copolymerization of TMC and ε‐caprolactone (ε‐CL) for the first time. The influence of reaction conditions, such as initiator, initiator concentration, polymerization temperature, and polymerization time, on monomer conversion, molecular weight, and molecular weight distribution of the resulting PTMC was investigated. It was found that the divalent complex 1 showed higher activity for the polymerization of TMC than complex 2 . The random structure and thermal behavior of the copolymers P(TMC‐co‐CL) have been characterized by ¹H NMR, ¹³C NMR, GPC, and DSC analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007