Synthesis and characterization of new polybenzoxazines from renewable resources for bio‐composite applications

Renewable natural resources such as eugenol, furfurylamine, stearylamine, and jute fiber were used to prepare polybenzoxazine composites. The purity of eugenol which is extracted from clove was confirmed by gas chromatography. FTIR, ¹H, and ¹³C NMR spectroscopic analysis were used to determine the structure of eugenol and the benzoxazine monomers namely 6‐allyl‐3‐furfuryl‐8‐methoxy‐3,4‐dihydro‐2H‐1,3‐benzoxazine (EF‐Bz) and 6‐allyl‐3‐octadecyl‐8‐methoxy‐3,4 dihydro‐2H‐1,3‐benzoxazine (ES‐Bz) synthesized from it. The curing analysis from differential scanning calorimetric analysis shows that the onset of curing is shifted to lower temperature (161°C) for EF‐Bz, when compared with ES‐Bz (174°C). The thermal stability analyzed from thermogravimetric analysis shows that the polybenzoxazine EF‐Pbz has higher thermal stability (T_5% = 361°C) with that of ES‐Pbz (T_5% = 313°C). The storage modulus, tensile, and flexural strength of the EF‐Bz/Jute fiber composite show high value when compared with ES‐Bz/Jute fiber composites. POLYM. COMPOS., 37:1821–1829, 2016. © 2014 Society of Plastics Engineers     

Synthesis of a novel series of propargyloxyphenyl maleimides and their characterization as thermal‐resistance resins

Novel thermosetting monomers possessing both maleimide and propargyl groups were first designed and synthesized. The monomers included N‐(2‐propargyloxyphenyl) maleimide (2‐PPM), N‐(3‐propargyloxyphenyl) maleimide (3‐PPM), and N‐(4‐propargyloxyphenyl) maleimide (4‐PPM), and their structures were confirmed with Fourier transform infrared (FTIR) spectroscopy, ¹H‐NMR, and elemental analysis. The cure behaviors of these monomers were characterized with differential scanning calorimetry and FTIR spectroscopy, and the results indicated that the monomers had a broader processing window than normal bismaleimide (BMI) resins. The thermal properties of the cured monomers were characterized with thermogravimetric analysis and dynamic mechanical analysis. The 5% mass loss temperatures of the cured monomers were high (ca. 400°C), and the glass‐transition temperatures of cured 2‐PPM, 3‐PPM, and 4‐PPM were 386, 373, and 387°C, respectively, which were much higher than those of typical commercial blended BMI resins. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Heat-resistant adhesive resins derived from bismaleimides and bisnadimides containing amide linkages

A novel class of bismaleimides and bisnadimides containing amide linkages in their backbones were synthesized and characterized. The synthesis of these polymer precursors was carried out by reacting a diamine containing amide linkages with maleic/nadic anhydride. They were alternatively prepared by reacting the monomaleamic/monoadiamic acid of an aromatic diamine (1 mol) with terephthaloyl chloride (0.5 mol) and subsequent cyclodehydration. The latter new preparation method circumvented the hydrogeneration necessary in the first method of synthesis. The monomers were characterized by infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Differential thermal analysis (DTA) of monomers showed that bisnadimide and bismethylnadimide were polymerized at lower temperatures than the corresponding bismaleimide. Thermogravimetric analysis (TGA) in nitrogen and air atmosphere revealed that all polymers were stable up to 321–363°C. Their char yield at 800°C under anaerobic conditions was 49–67%.     

Synthesis and characterization of poly(ester-urethane-imide)s by Diels–Alder polyaddition

Poly(ester-urethane-imide)s were prepared by Diels–Alder polyaddition of 1,6-hexamethylene-bis(2-furanylmethylcarbamate) with various bismaleimides containing ester groups in the backbone. The Diels–Alder reaction was carried out in m-cresol, at 110°C, followed by thermal and chemical aromatization of tetrahydrophthalimide intermediates. The monomers and polymers were characterized by IR, ¹H-NMR spectroscopy and elemental analysis. Thermal properties of the polymers were investigated by differential scanning calorimetry and dynamic thermogravimetric analysis.     

Synthesis and comparative study of thermal stabilities of the imidization of some maleic anhydride copolymers

In the present study, first, maleic anhydride‐styrene (MA‐St), maleic anhydride‐allyl phenyl ether (MA‐APhE), maleic anhydride‐heptene‐1(MA‐Hp), and maleic anhydride‐allyl propionate (MA‐AP) copolymers have been synthesized in different solvents in the presence of azobisisobutyronitrile (AIBN) at 70°C. Then, these four copolymers have been reacted with aniline at 60°C in N,N‐dimethyl formamide (DMF), and maleamidic acid derivatives of these copolymers have been synthesized. Next, they have been obtained from their maleimide derivatives by heating under vacuum at 150°C. All these polymers have been characterized by Fourier Transform infrared spectroscopy (FTIR) and investigated their thermal properties by using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) methods. The analyses results showed that thermal properties of maleimide derivatives of maleic anhydride copolymers changed as depend on the neighbor monomers of maleic anhydride. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2250–2254, 2006     

Synthesis,characterization, and studies on the solid-state crosslinking of functionalized vinyl cinnamate polymers

Functionalized vinyl cinnamate monomers were synthesized by the reaction between hydroxyethylacrylate (HEA) and substituted cinnamoyl chlorides possessing electron releasing and withdrawing functional groups like chloro, methoxy, and nitro groups at the para position of the aromatic ring. The structures of these monomers were characterized by Fourier transform infrared (FTIR), ¹H-, and ¹³C-NMR spectral techniques. The homopolymers of the synthesized monomers were obtained by the free radical solution polymerization in dimethylformamide (DMF) at 80°C for 12 h using azobisisobutyronitrile (AIBN) as a radical initiator. The sensitivity of these polymers towards light was studied by monitoring the photocrosslinking nature of the polymers by ultraviolet (UV) and FTIR techniques. The effect of the functional groups on the crosslinking efficiency was studied and compared with that of the unsubstituted polymer. The cyclobutane-type addition mechanism involved in the photocrosslinking phenomena was confirmed by the above spectral studies in the functionalized vinyl cinnamate polymers. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 441–448, 1998     

Synthesis of a novel poly(aryl ether) with pendent N-phenylimide groups

A novel monomer with two N-phenylimide activating groups for the preparation of poly(aryl ether)s was investigated. A poly(aryl ether) was prepared by nucleophilic halide displacement from an aromatic dihalide monomer containing two N-phenylimide groups by sodium salts of bisphenol A. The monomers and the resulting polymer were characterized by FT-IR and ¹H NMR spectroscopy, elemental analysis and differential scanning calorimetry (DSC). The prepared polymer with a molecular weight of 6 300 and a polydispersity of 1.37 determined by GPC is readily soluble in polar aprotic solvents, e. g. dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP). Despite the low molecular weight the polymer is thermally stable up to 390°C and has a glass transition temperature of 218°C which is identical to that of ULTEM® poly(ether imide).     

Synthesis and characterization of quaternary ammonium ionomers

The cationic monomers, MPDMAC₁₆ and MPDMAC₁₈, were obtained by quaternization of methacrylamidopropyl–N,N′‐dimethylamine with n‐alkyl iodides (1‐iodohexadecane and 1‐iodooctadecane) in ethyl acetate. Hydrophobic ionomers of MPDMAC₁₆ and MPDMAC₁₈ with N‐substituted acrylamides were prepared at 60 ± 0.1°C in DMF using AIBN initiator. The cationic monomers and ionomers were characterized by ¹H‐ and ¹³C‐NMR spectroscopy. The copolymer composition was evaluated from elemental analysis data using carbon/nitrogen (C/N) ratio. The molecular weight distributions of ionomers were obtained from GPC analysis. Both the dilute solution and concentrated solution properties of ionomers were studied by viscometry at 30°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1100–1105, 2005     

Synthesis,polymerization, and properties of the allyl‐functional phthalonitrile

A novel bisphthalonitrile monomer containing allyl groups (DBPA‐Ph) had been synthesized via the reaction of diallyl bisphenol A (DBPA) and 4‐nitrophthalonitrile. The chemical structure of DBPA‐Ph was confirmed by ¹HNMR, ¹³CNMR, and FTIR spectroscopy. The curing behaviors and processability of DBPA‐Ph were studied by differential scanning calorimetry (DSC) and dynamic rheological analysis. The monomer manifested a two‐stage thermal polymerization pattern. The first stage was attributed to the polymerization of allyl groups and the second to the ring‐form polymerization of cyano groups. The result of dynamic rheological analysis indicated the monomer had wide curing window and the self‐catalyzed curing behavior. DBPA‐Ph polymers were prepared from the thermal polymerization with short curing time, showing high glass transition temperature (>350°C) and attractive thermal decomposition temperature (>430°C). The outstanding glass transition temperature, desirable thermo‐oxidative stabilities, good processability and sound process conditions could provide more applications to the DBPA‐Ph polymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41203.     

Condensation polymerization of multifunctional monomers and properties of related polyester resins. I. Polyester varnishes

This article discusses optimum conditions for polycondensation of multifunctional monomers. Reaction variables such as monomer concentration, temperature, and time were studied to optimize reaction conditions. The influence of the nature and concentration of catalysts was also investigated. The optimum reaction conditions consisted of polymerization in an 82% w/w m-cresol solution at 160°C for 2 h, continuous reaction at 200°C for 1.5 h at 230°C for 3.5 h, followed by 40 min under reduced pressure and at 200°C. The catalyst was 1.4 × 10^?3 mol % Zn(OAc)₂ · 2H₂O in dimethyl terephthalate. Polycondensation of ethylene glycol, 1,4-butanediol, pentaerythritol, and trifunctional monomers (glycerin or trimethanolpropane) with dimethyl terephthalate was carried out in m-cresol to produce polyester prepolymers. The synthesized prepolymers were mixed with commercial Desmodur CT-stable (a phenol-blocked polyisocyanate) to form one-component varnishes which were characterized by thermogravimetric analysis. Polyester modified with trimethanolpropane has higher thermal stability than the one modified with glycerin. After being coated onto treated copper wires, the magnetic wires were characterized according to the specification of Japanese Industrial Standards (JIS-C-2358) and were found to be acceptable.     

Synthesis and Characterization Of Oligo(azomethine) Hybrids. Part II

Summary The synthesis and characterization of aromatic oligo(azomethines) hybrids by thermal oligomerization of a new monomers is reported. The new oligo(azomethines) have been characterized using, FT-IR, ¹H-NMR and ¹³C-NMR spectroscopy, elemental analysis, thermo gravimetric and viscosimetric measurements. These oligomers were synthesized by the intermolecular reaction between the ester group and the amine group, and the resulting products contain simultaneously imine, amide and carboxylic acid groups. The soluble oligomers were fractionated and it was possible to obtain a materials of different solubility and molecular size. The oligomers have high thermal stability that reached a loss of mass even of 10% at 460 °C.     

Synthesis,characterization, and ligating behavior of poly[N,N‐p‐phenylene bisacryl (methacryl)amide]

Monomers of diacylated amine were synthesized by the reaction of acryloyl chloride or methacryloyl chloride with p‐phenylenediamine. Heating DMF solution of these monomers at 75°C in the presence of AIBN as an initiator gave the corresponding polymer. The solid metallopolymer complexes with different metal salts were isolated either by the in situ addition of the monomer, metal salt, and initiator at 75°C or by the reaction of the isolated polymer with the metal salt at 150°C. The monomers, polymers, and their metallopolymer compounds were characterized using elemental analysis, IR, NMR (¹H and ¹³C), and MS spectral measurements in addition to thermal analysis. The IR data showed that the coordinating atoms of the polymer are dependent on the reaction temperature. The ion selectivity of the isolated polymers toward different metal ions either for a single metal ion or in a mixture as aqueous solutions are studied by the batch techniques. Energy dispersive spectroscopy (EDS) measurements showed that both polymers are more selective to Hg²⁺ and Pb²⁺. The morphology of the polymers and their metallopolymer complexes at different temperature was also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2412–2422, 2006     

Polymerization of allyl esters derived from long-chain fatty acids and palm olein

Allyl esters of palm olein, palmitic, and oleic acids were synthesized by transesterification and esterification methods using KOH and absolute H₂SO₄ as catalysts, respectively. Three allyl esters, namely, allyl palmitate, allyl epoxystearate, and epoxidized allyl ester of palm olein, were successfully polymerized in the presence of t-butyl perbenzoate at 120°C to obtain oligomers with the average number of backbone atoms approximately equal to the number of skeletal atoms of the long-dangling side chains. The kinetic data of polymerization were conformed to the rate equation proposed by other workers. No oxirane cleavage was detected during the chain reaction. The melting behavior of these comb-shaped polymers was compared with that of their respective allylic monomers. The polymer of epoxidized allyl ester of palm olein exhibits a glass transition temperature at 204.4 K. The critical molecular weights of the polymers of allyl esters investigated are predicted to be not lower than 10⁴.     

Dimeric liquid crystalline thermosets from azo-containing diglycidyl ether cured by anhydride

A series of dimeric liquid crystalline (LC) epoxy monomers containing azobenzene group with central spacers of different lengths were synthesized and structurally characterized by ¹H NMR, ¹³C NMR, and elemental analysis. The mesogenic behavior of these monomers was measured by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction (XRD). Like other dimeric LC epoxy monomers, the melting points, clear points, and mesophase of these compounds are influenced by the carbon numbers of central spacers. Anhydride was employed to cure the monomers and LCTs with nematic phase were obtained. Thermal properties, dynamic mechanical properties and UV–Vis spectra of the LCTs were studied. The decomposition of the LCTs occurred near 220 °C and followed three stages. The LCTs also had the natural absorbance bonds of azo compounds.     

Photoresponsive Functionalized Vinyl Cinnamate Polymers: Synthesis and Characterization

A series of functionalized vinyl cinnamate monomers were synthesized by the reaction of hydroxyethylmethacrylate and various substituted cinnamoyl chlorides. Electron donating and accepting functional groups such as −OCH₃, −Cl and −NO₂ were introduced at the para position of cinnamoyl chloride. Homopolymerization of the synthesized monomers were carried out in dimethylformamide using azobisisobutyronitrile as a free radical initiator at 80°C for 12h. The structures of the synthesized monomers and their polymers were characterized using Fourier transform infrared (FTIR), ¹H and ¹³C nuclear magnetic resonance spectroscopic techniques. Solid-state crosslinking of the above photosensitive polymers was studied by UV and FTIR spectroscopic techniques. The effects of various functional groups and the addition of sensitizer (benzophenone) on the photocrosslinking nature of the polymers were studied. The mechanism of photocrosslinking is a (2+2)π electron cycloaddition and not cis–trans isomerization in the functionalized polyvinylcinnamates. © 1997 SCI     

Radical polymerization of new functional monomers: Mono- and dimethacryloyl isocyanate containing bisphenol-A and its derivatives

New functional monomers mono-and dimethacryloyl isocyanate containing bisphenol-A were prepared on reaction of methacryloyl isocyanate (MAI) with bisphenol-A (BPA) and its derivatives at low temperature. The monomers thus obtained were characterized with IR, UV, and ¹H- and ¹³C-NMR spectra. Radical polymerization of mono-and dimethacryloyl isocyanate containing bisphenol-A and its derivatives was studied in terms of the rate of polymerization, solvent effect, copolymerization, thermal properties, and kinetic measurements of photocrosslinking. Polar solvents such as DMSO and NMP were found to slow the polymerization. Copolymerization of BPA-MAI (M₁) with MMA (M₂) in DMF was studied at 90°C. The monomer reactivity ratio was calculated to be r₁ = 0.17 and r₂ = 1.34 according to the method of Fineman–Ross. Functional polymers containing the allyl group were successfully modified and photocrosslinked on irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process follows second-order kinetics. © 1996 John Wiley & Sons, Inc.     

Studies on adhesion of allylic resin. I. Adhesion of diallylphthalate resin and dichromate-treated copper foil

An effective copper surface treatment for adhesive bonding of copper foil and diallylphthalate resin was investigated. It involves dipping the copper foil in the potassium dichromate-sulfuric acid solution (K₂Cr₂O₇:76 g/l, H₂SO₄:0.67 N) at 60°C for 5 min. The dichromate treated copper foil and glass based prepregs of diallylphthalate resin were laminated under the pressure of 38 kg/cm² for 30 min at 145°C. Interface characteristics of the dichromate treated copper foil and diallylphthalate resin were examined. It was found that chromium is formed on the surfaces of the treated copper foil, and allyl groups in diallylphthalate molecule are oriented to the atoms, that is, the adhesive bonding is performed by the chemical affinity of chromium and allyl groups. The allyl group has a delocalized π-electron system, and that its bonding to a transition metal as chromium is appropriate and justifiable by quantum chemical considerations.     

Synthesis,Characterization, Reactivity Ratio and Photo Crosslinking Properties of the Copolymer of 4-Cinnamoyl Phenyl Methacrylate with Butyl Methacrylate

Copolymers of 4-cinnamoyl phenyl methacrylate (4-CPMA) and n-butyl methacrylate (BMA) were prepared in a methyl ethyl ketone (MEK) solution with benzoyl peroxide (BPO) as an initiator at 70°C. They were characterized with UV, IR, ¹H-NMR, ¹³C-NMR, TGA, DSC and gel permeation chromatography. Copolymers were prepared by using different feed ratio of monomers. The monomer reactivity ratios determined by the method of Kelen-Tudos (K-T) were r₁ (CPMA) = 2.32, r₂ (BMA) = 0.56. The glass transition temperature of the copolymer shows a single Tg indicating the formation of random copolymer for all of the monomer feed composition. Thermogravimetric analysis in air has shown that the initial decomposition temperature of the copolymer was above 220°C. The photocrosslinking properties of the copolymer were examined by UV irradiation with polymer film.     

Thermal and physical properties of allyl PPO and its composite

The thermal behavior of allyl PPO and its cured resin were investigated. In the allyl PPO curing process, the specific temperatures were T_gel = 173.6°C, T_cure = 225.4°C, and T_treat = 237.7°C, and the activation energy (E_a) was 122 kJ/mol. The average number of PPO molecular units between two crosslinking points was about 20. In the degradation process of cured allyl PPO resin, the temperature at which mass loss equaled 1% was much higher than 300°C. The E_a for degradation was calculated as 125 kJ/mol, with a degradation fraction (α) in the range of 0.15–0.65, or 117 kJ/mol with an α of 0.10–0.90. The most probable mechanism function of decomposition of the cured allyl PPO resin was f(α) = 2(1 ? α)^3/2 or g(α) = (1 ? α)^?1/2 ? 1. The thermocompressed laminate of the allyl PPO blending with an additive resin (made from BDM and DP) exhibited the desired properties. ©2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4111–4115, 2006     

Synthesis and characterization of poly(ether carbonate)s by melt‐phase interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether groups

A new method of synthesis of poly(ether carbonate)s based on interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether group was presented. The diphenyl dicarbonate monomers were prepared from phenyl chloroformate and dihydroxy compounds containing ether group (e.g., diethylene glycol, bis(2‐hydroxyethyl ether) of bisphenol A, and 4,4′‐oxydiphenol). The process consisted of a precondensation step under a stream of dry argon followed by a melt polycondensation at 230 or at 250°C under vacuum. Four series of poly(ether carbonate)s were prepared using this approach. Using alkylene and arylene diphenyl dicarbonate‐containing ether groups as monomers, the polycondensation reaction with dihydroxy compounds led to the formation of poly(ether carbonate)s having inherent viscosity values up to 0.56 dL/g and high thermal stability. The glass transition temperature values of polycarbonates were in the range 7–122°C. The polymers were characterized by inherent viscosity and spectroscopic (Fourier transform infrared spectroscopy and ¹H‐NMR and ¹³C‐NMR) and thermal (differential scanning calorimeteric and thermogravimetric) methods. This approach may permit the use of diphenyl dicarbonates containing other organic functional groups for the synthesis of polycarbonates containing those groups. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012