Acetylation of cellulose using recyclable polymeric catalysts

The esterification of cellulose with acetyl chloride in N‐methyl‐2‐pyrrolidinone proceeded smoothly using crosslinked polyvinylpyridine (C‐PVP) as catalysts. The structures of the cellulose acetates were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR analyses. The molecular weights were determined by GPC, and the thermal properties were characterized with DSC and TGA. The effects of reaction conditions on yields and degree of substitutions were evaluated in detail. C‐PVP was recycled by a simple alkali treatment, and the recycled C‐PVP could be readily reused as catalysts in cellulose acetylations without adverse effects on the reactions. The influences of C‐PVP on the structures of cellulose acetate samples were further discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3288–3296, 2006     

Synthesis and Characterization of Estolide Esters Containing Epoxy and Cyclic Carbonate Groups

The unsaturated sites in oleic 2‐ethylhexyl estolide esters (containing 35 % monoenic fatty acids) were converted into epoxide and five‐membered cyclic carbonate groups and the products characterized by Fourier transform infrared spectra (FTIR), ¹H, and ¹³C nuclear magnetic resonance (NMR) spectroscopies. Epoxidation of the alkene bonds was accomplished using performic acid generated in situ from formic acid and hydrogen peroxide. Greater than 90 % alkenes were converted into their corresponding epoxide groups as determined by oxirane values and the epoxide ring structure was confirmed by ¹H and ¹³C NMR. The estolide ester epoxide material was subsequently reacted with supercritical carbon dioxide in the presence of tetrabutylammonium bromide catalyst to produce the corresponding estolide ester containing the cyclic carbonate group. The signals at 1,807 cm^?1 and δ 82 ppm in the FTIR and ¹³C‐NMR spectra, respectively, confirmed the desired cyclic carbonate was produced. The carbonated estolide ester exhibited a dynamic viscosity, at 25 °C, of 172 mPa·s as compared to 155 mPa·s for the estolide ester starting material. The estolide ester structure of these new derivatives was shown to be consistent throughout their synthesis.     

Influence of the structure of the onium iodide salts on the properties of modified montmorillonite

Dialkyl imidazoline, alkyl pyridine and alkyl quinoline containing salts have been synthesized and used as new surfactants for cationic exchange of layered silicates, such as montmorillonite (MMT) in order to evaluate their role in the formation of intercalated MMT clays. The new salts have been characterized by FTIR, ¹H, ¹³C‐NMR spectra. These compounds have been intercalated into the layers of MMT via a solution dispersion technique and the extent of the interlayer space expansion was confirmed by using wide angle X‐ray diffraction and FTIR spectra. Thermogravimetry analysis shows that these salts can be used in place of ammonium salts to produce organophilic clays with higher thermal stability than commercial alkyl ammonium‐treated MMT. Moreover, the results also show that the imidazolium‐modified clays have a greater thermal stability compared to the quinolinium and the pyridinium‐modified clay. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Graft copolymers of lignin from straw with 1‐ethenylbenzene: Synthesis and characterization

The synthesis of copolymers between lignin from steam‐exploded straw and 1‐ethenylbenzene is described. Beforehand, lignin from steam‐exploded straw was fully characterized by using elemental analysis, ultraviolet spectroscopy, gel permeation chromatography (GPC), Fourier transform infrared (FTIR), and both ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. Using a previously described procedure utilizing calcium chloride and hydrogen peroxide as reagents the synthesis of the copolymers was performed. FTIR of the copolymers showed the presence of both lignin and polystyrene. GPC analysis showed the presence of a fraction with high molecular weights. These results were confirmed from both viscosity data and differential calorimetry. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 72–79, 2001     

Complexation of titanium alkoxides with pentenoic acid and allylacetoacetate and their hydrolysis and addition reactions with H‐silanes

Complexation reactions of titanium tetraethoxide [Ti(OEt)₄] and titanium tetra‐n‐butoxide [Ti(OBuⁿ)₄] with 3‐pentenoic acid (PA) and allylacetoacetate (AAA), in a 1 : 1M ratio, were studied in ethanol solution at room temperature. ¹³C‐NMR and FTIR spectra showed that all PA and AAA completely reacted with both titanium alkoxides. Hydridosilane compounds such as triethoxysilane and triethylsilane were added to titanium chelate complexes in a 1 : 1M ratio. The investigation of products by ¹³C‐ and ²⁹Si‐NMR and FTIR showed additions of ? SiH to the C?C double bond. The hydrolysis of titanium–PA and AAA complexes, by water in 1 : 4 ratios, resulted in released PA in an amount of 10% and AAA of 20%. The stability of hydrolyzed products was investigated by ¹³C‐NMR, ²⁹Si‐NMR, and FTIR. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 790–796, 2005     

Microstructure analysis of poly(styrene‐co‐vinylidene chloride) copolymers by NMR spectroscopy

Poly(styrene‐co‐vinylidene chloride) (S/V) copolymers were prepared by free‐radical photopolymerization using uranyl nitrate as an initiator. The microstructure of the copolymer S/V was investigated by ¹H‐ and ¹³C{¹H}‐NMR, ¹H–¹³C‐heteronuclear shift quantum correlation (HSQC) NMR, and homonuclear total correlated spectroscopy (TOCSY). The ¹H‐NMR spectra of the copolymers is complex due to overlapping resonance signals of the various triad configurations. Assignments were made up to the triad and tetrad levels for the methylene and methine regions using two‐dimensional HSQC experiments. A ¹³C‐distortionless enhancement by polarization transfer (DEPT) spectrum was used to differentiate between the carbon resonance signals of methine and the methylene units. The geminal couplings in the methylene protons and vicinal coupling between the methine and methylene protons were detected from the TOCSY spectra. Monte Carlo simulations were used to investigate the effect of the degree of polymerization on the triad fractions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 544–554, 2001     

Reactivity,chemical structure,and molecular mobility of urea–formaldehyde adhesives synthesized under different conditions using FTIR and solid‐state 13C CP/MAS NMR spectroscopy

This study was conducted to investigate the effects of reaction pH condition and hardener type on the reactivity, chemical structure, and molecular mobility of urea–formaldehyde (UF) resins. Three different reaction pH conditions, such as alkaline (7.5), weak acid (4.5), and strong acid (1.0), were used to synthesize UF resins, which were cured by adding four different hardeners (ammonium chloride, ammonium sulfate, ammonium citrate, and zinc nitrate) to measure gel time as the reactivity. FTIR and ¹³C‐NMR spectroscopies were used to study the chemical structure of the resin prepared under three different reaction pH conditions. The gel time of UF resins decreased with an increase in the amount of ammonium chloride, ammonium sulfate, and ammonium citrate added in the resins, whereas the gel time increased when zinc nitrate was added. Both FTIR and ¹³C‐NMR spectroscopies showed that the strong reaction pH condition produced uronic structures in UF resin, whereas both alkaline and weak‐acid conditions produced quite similar chemical species in the resins. The proton rotating‐frame spin–lattice relaxation time (T_1ρH) decreased with a decrease in the reaction pH of UF resin. This result indicates that the molecular mobility of UF resin increases with a decrease in the reaction pH used during its synthesis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2677–2687, 2003     

Thermally activated polymerization behavior of bisphenol‐S/methylamine‐based benzoxazine

A bifunctional benzoxazine monomer, 6,6′‐bis(3‐methyl‐3,4‐dihydro‐2H‐benzo[e] [1,3]oxazinyl) sulfone (BS‐m), was synthesized from bisphenol‐S, methylamine, and formaldehyde via a solution method. The chemical structure of BS‐m was characterized with ¹H and ¹³C‐nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The ring‐opening polymerization reaction of BS‐m monomer was studied by FTIR, ¹³C solid‐state NMR, and differential scanning calorimetry. With the polymerization reaction proceeding, the intensities of the FTIR absorption peaks of CH₂, C? O? C, and C? N? C of the oxazine ring decreased gradually, and some of these absorption peaks disappeared. The shapes and intensities of the absorption peaks associated with benzene ring, sulfone group, and aromatic C? S bond changed in various ways. The changes in the solid‐state ¹³C‐NMR pattern, including chemical shifts, intensity of resonances, and line‐width, were observed from the spectra of BS‐m and the corresponding polybenzoxazine. The melting process of BS‐m overlapped with the beginning of the ring‐opening polymerization reaction. The polymerization kinetic parameters were evaluated for nonisothermal and isothermal polymerization of BS‐m. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Graft copolymers of lignin with electron poor alkenes

The synthesis of copolymers between lignin and electron poor alkenes is described. Lignin from steam‐exploded pine, from steam‐exploded straw, and organosolv were used as starting materials. Beforehand, lignins were fully characterized by using elemental analysis, ultraviolet spectroscopy, gel permeation chromatography (GPC), Fourier transform infrared (FTIR), and both¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The synthesis of copolymers was performed using a previously described procedure utilizing calcium chloride and hydrogen peroxide as reagents. FTIR of copolymers showed absorptions due to the presence of both lignin and the electron withdrawing group on the alkene. GPC analysis showed the presence of fractions with high molecular weights: the M_z of lignin from pine was 3729 while the copolymer with methyl acrylate showed M_z = 383790. Differential calorimetry showed the presence of glass transitions in the range of ?9 to 4.5°C due to the presence of grafted polyalkene chains. When acrylonitrile was used as starting material DSC analysis of the product showed a glass transition at 119°C, which can be attributed to grafted polyacrylonitrile chain. Lignin from steam explosion could be a good raw material in the preparation of graft copolymers. Furthermore, lignin from pine gave better results than that from straw. Finally, lignin from steam explosion gave better results than organosolv lignin. These results can be explained on the basis of the structural properties of used lignins. Both UV and ¹³C NMR spectra showed that lignin from pine contained a consistent amount of double bonds. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1163–1171, 2003     

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Four alkyl lactates and alkyl lactate acrylates having methyl, ethyl, propyl, and butyl as alkyl moiety were synthesized by azeotropic distillation. Their formation was confirmed by Fourier transform infrared (FTIR), mass, ¹H nuclear magnetic resonance (NMR) and proton decoupled ¹³C NMR spectroscopic techniques. Solution polymerization was carried out for these alkyl lactate acrylates and the formed homopolymers were characterized by FTIR, ¹H NMR, proton decoupled ¹³C NMR spectroscopic, and gel permeation chromatographic techniques. Shear thinning behavior was observed for all the polymers. Wide angle X‐ray Diffraction studies showed that the polymers were amorphous in nature and also exhibited odd‐even effect among alkyl lactate groups with respect to average molecular interchain spacing. Depending on the length of the alkyl lactate groups, relative humidity and time, the hydrophilicity of the polymers decreased with increase in the length of the alkyl lactate group among the odd and even series. Among the studied polymers, poly(ethyl lactate acrylate) may have the potential for hydrogel applications, due to its highly hydrophilic nature. T_g decreased with increase in length of alkyl lactate groups. Trend observed on the thermal stabilities of poly(alkyl lactate acrylate)s could be explained on the basis of average molecular interchain spacing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40962.     

Preparation and properties of water‐soluble polyester surfactants. III. Preparation and wetting properties of polyethylene glycol–polydimethylsiloxane polyester surfactants

A novel series of water‐soluble polyethylene glycol–polydimethylsiloxane (PEG–Silicone) polyesters was prepared by reacting organopolysiloxane with hydroxyl‐terminated polyester. The polyesters are obtained by the polymerization of maleic anhydride (MA) and PEGs (number‐average molecular weights M _n = 2000–10,000). FTIR, ¹H‐NMR, and elemental analysis were employed to characterized the structures of these compounds. These compounds exhibit good surface activities such as surface tension and low foaming. The influence of the PEG–Silicone polyester surfactants introduced at various concentrations (0.1–2 wt %) was examined by the contact angle method. The measurements performed with various solid substrates indicated that, at comparable concentrations, the PEG–Silicone polyester surfactants were shown to be more efficient for wetting PET and glass. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1236–1241, 2003     

The properties of epoxy–imide resin cured by phosphorylated diamines containing different alkyl groups on phosphorus

Cured networks of epoxy–imide resin cured with four types of phosphorylated diamine curing agents that contained different alkyl groups on phosphorus were studied. The structures of these novel phosphorus‐containing curing agents were confirmed by Mass, EA, IR, and ¹H‐NMR and ¹³C‐NMR spectra characterization. The reactivities were measured by differential scanning calorimetry (DSC). It is found that the reactivities were not affected by the types of alkyl groups in the curing agents. In thermal gravimetric analysis (TGA), those polymers that were obtained through the curing reactions between epoxy–imide resin and four curing agents (BAMP, BAEP, BAPP, and BABP) also demonstrated excellent thermal properties as well as a high char yield. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 141–147, 2002     

NMR and IR study of kaolinite intercalation compounds with benzylalkylammonium chlorides

Novel intercalation compounds of kaolinite with selected benzylalkylammonium chlorides, obtained using methoxy-kaolinite as a precursor, were characterized by ¹³C, ²⁷Al, and ²⁹Si solid-state NMR and infrared (FTIR) spectroscopy. The analyses allowed the confirmation of both the formation and structure of precursors (kaolinite-dimethyl sulfoxide and methoxy-kaolinite), as well as the intercalation compounds. According to the ¹³C CP-MAS NMR spectra of the derivatives with benzyltrimethylammonium chloride (B1), the methyl groups of the molecules, arranged in a monolayer, were keyed into the ditrigonal holes of the kaolinite tetrahedral sheet. The local environment of internal carbons of benzyltributylammonium chloride (B2) butyl chains was mostly perturbed during intercalation. In turn, the structure of the benzyldimethylhexadecylammonium chloride (B5) after intercalation was changed from the solid-like to liquid-like conformation with an increase of gauche conformers, which was attested both by ¹³C CP-MAS NMR and FTIR. The ¹³C CP-MAS NMR analysis confirmed that the methoxyl groups attached to the octahedral surface of methoxy-kaolinite were not affected by intercalation. The ²⁷Al and ²⁹Si MAS NMR did not show any significant distortion of the Al-octahedra and Si-tetrahedra after intercalation of the organic salts. The IR analyses indicated an increased amount of intercalated water with the increase of initial salt concentration.     

Synthesis and optical properties of poss‐based oxadiazole nanohybrids with three‐dimensional molecular conjugated structure

A series of oxadiazole‐containing molecular hybrid materials with three‐dimensional structure ( P1–P3 ) was prepared by Heck reaction based on the octavinylsilsesquioxane. All resultant hybrid materials are soluble in common organic solvents and possess good film‐forming property. Their structures and properties were characterized and evaluated by FTIR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, MALDI‐TOF, UV–vis, photoluminescence (PL), cyclic voltammetry, and elemental analysis (EA). The results showed that the substituted arm numbers of hybrids ( P2 and P3 ) with pushing electron groups were efficiently controlled. Moreover, the hybrids possessed a steady blue emission and good electron‐injecting property in film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40246.     

Syntheses,antitumour activities and antiangiogenesis of 1,2,3‐tris(ethoxycarbonyl)‐2‐propyl acrylate and its polymers

A new monomer, 1,2,3‐tris(ethoxycarbonyl)‐2‐propyl acrylate (TPA), was synthesized by reaction of acryloyl chloride and triethyl citrate. The homopolymer of TPA and its copolymers with acrylic acid (AA), vinyl acetate (VAc) and maleic anhydride (MAH) were prepared by polymerization using lauroyl peroxide (LPO) at 70 °C for 24 h. The structures of TPA and its polymers were identified by FTIR, ¹H NMR, ¹³C NMR spectroscopies, and elemental analysis. The number average molecular weights and polydispersity indices of the synthesized polymers determined by GPC were in the range 4200–23 000 g mol^?1 and 1.1–2.1, respectively. The IC₅₀ values of the synthesized samples against cancer cell lines were greater than those of 5‐fluorouracil (5‐FU). The percentage inhibition values of SV40 DNA replication were 82.2 for TPA, 34.3 for poly (TPA), 81.9 for poly(TPA‐co‐AA), 82.0 for poly(TPA‐co‐VAc), 35.6 for poly(TPA‐co‐MAH) and 12.7 for 5‐FU. The inhibitions of SV40 DNA replication and antiangiogenesis for the synthesized TPA and its polymers are much greater than those of the control. © 2001 Society of Chemical Industry     

Chemical modification of chitosan: Synthesis and characterization of chitosan‐crown ethers

Four novel Schiff‐type chitosan (CTS)‐crown ethers were synthesized through a reaction between ? NH₂ in CTS or crosslinked chitosan (CCTS) and ? CHO in 4′‐formylbenzo‐crown ethers, and four secondary‐amino‐type CTS‐crown ethers were prepared through the reduced reaction of NaBH₄, respectively. Their structures were characterized by elemental analysis, Fourier transform infrared (FTIR) spectra analysis, solid‐state ¹³C‐NMR analysis, and X‐ray diffraction (XRD) analysis. The elemental analysis results showed that the percentage of nitrogen in all CTS‐crown ethers were lower than that of CTS or CCTS. From the FTIR data of CTS, CCTS, and CTS‐crown ethers I–VIII, we saw that the characteristic peaks of C?N, N? H, and Ar appeared and that the characteristic peaks of pyranoside in the chain of CTS or CCTS were not destroyed. The XRD spectra demonstrated that CTS‐crown ethers I–VIII gave lower crystallinities than CTS or CCTS, which indicated that these compounds were considerably more amorphous than CTS or CCTS. In the solid‐state ¹³C‐NMR spectra, all of these CTS‐crown ethers had a particular peak of aromatic at 128 or 129 ppm, and the greatest difference between Schiff‐type CTS‐crown ethers and secondary‐amino‐type CTS‐crown ethers was that the Schiff‐type CTS‐crown ethers had the particular peak of C?N, which disappeared in secondary‐type CTS‐crown ethers. All these facts confirmed that the structures of CTS‐crown ethers I–VIII were as expected. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2221–2225, 2003     

Castor‐acrylated monomer 1H‐ and 13C‐nuclear magnetic resonance spectral assignments

Castor‐acrylated monomer (CAM) NMR spectral assignments were made utilizing one‐ and two‐dimensional NMR techniques. The unique structure of CAM resulted in several novel chemical environments which were observed in the NMR spectra. Previously published vegetable oil and fatty acid ester NMR peak assignments were insufficient for complete identification of NMR peaks. Definitive peak assignments, particularly in the alkyl and alkene regions, are required for evaluation of CAM as a specialty comonomer in the synthesis of latex polymers for use as waterborne‐coating binders. The NMR peak assignments for CAM will allow the subsequent evaluation of the copolymerizability of CAM as well as the determination as to whether unsaturation is preserved during latex polymer synthesis. ¹H‐ and ¹³C‐NMR spectra of CAM are provided with supporting evidence for the peak assignments and discussion of their relevance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1850–1854, 2001     

Etherification of hemicelluloses from sugarcane bagasse

Conditions for the preparation of etherified hemicelluloses from sugarcane bagasse with 2, 3‐epoxypropyltrimethylammonium chloride (ETA) using sodium hydroxide as a catalyst in aqueous solution were studied comparatively. The extent of the etherification was measured by yield percentage and degree of substitution. The effects of reaction time of 3–7 h, reaction temperature of 50–80°C, temperature of alkaline activation of 30–60°C, and time of alkaline activation of 0–60 min on the reaction yield and degree of substitution were investigated in detail. The overall yield and degree of substitution were varied from 35.2 to 41.9% and from 0.14 to 0.33, respectively, by changing the reaction temperature and duration as well as time and temperature of alkaline activation. The new materials were characterized by FT‐IR and 13C NMR spectroscopy, thermal analysis as well as GPC. It was found that the thermal stability of the hemicellulosic ethers decreased after chemical modification, and the molecular weights of the etherified hemicelluloses were lower than those of the native hemicelluloses. ¹³C NMR spectra gave the evidence for etherification reaction and the quaternization of hemicelluloses occurred mainly at C‐3 position. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

13C‐NMR, 13C‐13C gCOSY,and ESI‐MS characterization of ether‐bridged condensation products in N,N′‐dimethylurea‐formaldehyde systems

The reaction of urea with formaldehyde is the basis for the production of urea‐formaldehyde (UF) resins which are widely applied in the wood industry. The presence of ether‐bridged condensation products in the UF resin reaction system is an open question in the literature. It is addressed in the present work. The N,N′‐dimethylurea‐formaldehyde model system was studied since it is chemically similar to the UF resin reaction system but allows for a simple elucidation of all reaction products. It was analyzed by ¹³C‐NMR spectroscopy and ESI‐MS. In corresponding NMR and MS spectra, peaks due to methoxymethylenebis(dimethyl)urea and its hemiformal were observed. ¹³C‐¹³C gCOSY analysis was conducted using labeled ¹³C‐formaldehyde. The correlation spectra showed evidence for an ether‐bridged compound and mass spectra exhibited peaks agreeing with labeled methoxymethylenebis(dimethyl)urea and its hemiformal. Methoxymethylenebis(dimethyl)urea was characterized in N,N′‐dimethylurea‐formaldehyde systems in acidic and slightly basic media. As urea is very similar to N,N′‐dimethylurea, the results of this work strengthen the assumption that ether‐bridged condensation products are likely to form in UF resins. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Formation of polymethylsiloxanes with alkyl side groups

Hydrosilylation of α,ω‐bis(trimethylsiloxy)methylhydrosiloxane to alkenes in the presence of a catalyst was performed at several temperatures (30–70°C). Comb‐type methylsiloxane oligomers with various alkyl substituted groups in the side chains have been obtained. Not all active ≡Si? H groups participate in the reaction. The reaction order, activation energies, and rate constants have been determined. The synthesized oligomers were characterized by ¹H, ¹³C, ¹H COSY NMR, and FTIR spectroscopy. Calculations using the quantum‐chemical semiempirical AM1 method for modeling reaction between methyldimethoxysilane [Me(MeO)₂SiH] and hexene‐1 were performed to evaluate possible reaction paths. For all initial, intermediate, and final products, enthalpies of formation as a function of the distance between ≡C? Si≡ bonds are calculated. The hydride addition is energetically more favorable according to the anti‐Markovnikov rule than according to the Markovnikov rule. Comb‐type oligomers were characterized by gel‐permeation chromatography, differential scanning calorimetry, thermogravimetry, and wide‐angle X‐ray diffractometry. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1176–1183, 2007