Synthesis and electrical properties of copolymers of o‐phenylenediamine with aniline, 3,4‐ethylenedioxythiophene and 2,3,5,6‐tetrafluoroaniline

Copolymers (P(PDA/Ar)) of o‐phenylenediamine with aniline (Ar = ANi), 3,4‐ethylenedioxythiophene (Ar = EDOT) and 2,3,5,6‐tetrafluoroaniline (Ar = TFANi) were synthesized via polycondensation initiated by ammonium persulfate. The NH₂ group content in the copolymers was determined by analyzing the ¹H NMR spectra of the N‐acetylated copolymers. Copolymers crosslinked by viologen (1,1'‐disubstituted 4,4'‐bipyridinium dichloride) were obtained by reaction involving the reactive NH₂ groups in the copolymers. The absorption wavelengths of solutions of the copolymers and the electrochemical oxidation and reduction potentials of cast films of the copolymers were affected by the electrical properties of the Ar unit. © 2016 Society of Chemical Industry     

Synthesis and characterization of poly[(butylene succinate)‐co‐(butylene terephthalate)]‐b‐poly(tetramethylene glycol) segmented block copolymer

Polyester‐polyether segmented block copolymers of poly[(butylene succinate)‐co‐poly(butylene terephthalate)] (PBS–PBT) and poly(tetramethylene glycol) (PTMG) (M_n = 2000) with various compositions were synthesized. PBT content in the PBS was adjusted to ca. 5 mol %. Their thermal and mechanical properties were investigated. In the case of copolymer, the melting point of the PBS–PBT control was 107.8°C, and the melting point of the copolymer containing 70 wt % of PTMG was 70.1°C. Crystallinity of soft segment was 5 ∼ 17%, and that of hard segment was 42 ∼ 59%. The breaking stress of the PBS–PTMG control was 47 MPa but it decreased with increasing PTMG content. In the case of copolymer containing 70 wt % of PTMG, breaking stress was 36 MPa. Contrary to the decreasing breaking stress, breaking strain increased from 300% for PBS–PBT control to 900% for a copolymer containing 70 wt % of PTMG. The shape recovery ratios of the copolymer containing 70 wt % PTMG were almost twice of those of copolymers containing 40 wt % PTMG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2067–2075, 2001     

Fabrication,structures, and properties of acrylonitrile/methyl acrylate copolymers and copolymers containing microencapsulated phase change materials

The polyacrylonitrile‐methyl acrylate (AN/MA mole ratio 100/0–70/30) copolymers and copolymers (AN/MA mole ratio 85/15) containing up to 40 wt % of microencapsulated n‐octadecane (MicroPCMs) are synthesized in water. The MicroPCMs were incorporated at the step of polymerization. The effect of the MA mole ratio and MicroPCMs content on structures and properties of the copolymers were studied by using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H NMR), scanning electronic microscope (SEM), differential scanning calorimetry (DSC), thermogravimetry analysis (TG), gel permeation chromatography (GPC), and X‐ray diffraction (XRD). The feeding ratio agreed well with the composition of the AN/MA copolymers. The copolymers are synthesized in the presence of MicroPCMs. The melting point moves to lower temperature (206°C), while the decomposition temperature moves to higher temperature (309°C) with increasing of the MA mole ratio and microcapsules content. The number–average molecular weight of the copolymer is ～30,000. The crystallinity of the copolymer decreases with increasing of the MA mole ratio and microcapsules content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2776–2781, 2007     

Preparation and characterization of acrylonitrile‐ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile‐co‐ethyl methacrylate), P(AN‐EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO₄ salt loaded (PAN‐co‐PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac‐conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Grafting of poly(3‐hydroxyalkanoate) and linoleic acid onto chitosan

Poly(3‐hydroxy octanoate) (PHO), poly(3‐hydroxy butyrate‐co‐3‐hydroxyvalerate) (PHBV), and linoleic acid were grafted onto chitosan via condensation reactions between carboxylic acids and amine groups. Unreacted PHAs and linoleic acid were eliminated via chloroform extraction and for elimination of unreacted chitosan were used 2 wt % of HOAc solution. The pure chitosan graft copolymers were isolated and then characterized by FTIR, ¹³C‐NMR (in solid state), DSC, and TGA. Microbial polyester percentage grafted onto chitosan backbone was varying from 7 to 52 wt % as a function of molecular weight of PHAs, namely as a function of steric effect. Solubility tests were also performed. Graft copolymers were soluble, partially soluble or insoluble in 2 wt % of HOAc depending on the amount of free primary amine groups on chitosan backbone or degree of grafting percent. Thermal analysis of PHO‐g‐Chitosan graft copolymers indicated that the plastizer effect of PHO by means that they showed melting transitions T_ms at 80, 100, and 113°C or a broad T_ms between 60.5–124.5°C and 75–125°C while pure chitosan showed a sharp T_m at 123°C. In comparison of the solubility and thermal properties of graft copolymers, linoleic acid derivatives of chitosan were used. Thus, the grafting of poly(3‐hydroxyalkanoate) and linoleic acid onto chitosan decrease the thermal stability of chitosan backbone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:81–89, 2007     

Synthesis and characterization of emulsion copolymer of N‐cyclohexylmaleimide and methyl methacrylate

Copolymers of N‐cyclohexylmaleimide (ChMI) and methyl methacrylate (MMA) were synthesized by the emulsion semibatch copolymerization method. The effects of the monomer mixture composition on the average molecular weight (M_n and M_w ), glass transition temperature (T_g), degradation temperature, mechanical properties, and rheological behavior of the copolymers were investigated. The results show that M_n and M_w have maximum values when the ChMI feed content was about 20% (by wt). The degradation temperature and T_g of the copolymers increase with increasing ChMI moieties in the copolymer. The mechanical properties (tensile strength and impact strength) decrease with an increasing ChMI feed content. All copolymers in the melt show pseudoplastic behavior. The flow index n increases with an increasing ChMI feed content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1070–1075, 2002; DOI 10.1002/app.10394     

Synthesis and properties of copolymers of poly(ether ether sulfone)/semiaromatic polyamides (PEES/PA)

Poly(ether ether sulfone) (PEES) containing semi‐aromatic polyamides with methylene units and ether linkage were synthesized through the copolymerization of m‐dihydroxybenzene, 4,4‐dichlorodiphenylsulfone (DCDPS) and 1,6‐N, N′‐bis(4‐fluorobenzamide) hexane (BFBH) by the method of nucleophilic polymerization. The inherent viscosities of the resultant different proportion of copolymers were in the range of 0.39–0.78 dL/g. These copolymers were found to have excellent thermal properties with glass transition temperatures (T_g) of 121–177°C, and initial degradation temperatures (T_d) of 417.5–432.5°C. These copolymers showed good mechanical properties with tensile strengths of 45–83 MPa, storage modulus of 1.8–2.6 GPa. The complex viscosities of pure Poly(ether ether sulfone) (PEES) was in the range of 176,000–309.8 Pas from 0.01 to 100 Hz, the complex viscosities of the copolymers decreased significantly with the increase of semi‐aromatic amide content, the copolymers of 20% decreased from 4371 to 142.4 Pas (from 0.01 to 100 Hz), and the copolymers of 70% dropped from 634.6 Pas to 55.97 Pas (from 0.01 Hz to 100 Hz). All copolymers exhibited non‐Newtonian and shear‐thinning behavior. These results suggested the resultant copolymers possess better melt flowability that is beneficial for the materials’ melt processing. POLYM. ENG. SCI., 56:44–50, 2016. © 2015 Society of Plastics Engineers     

Stimuli sensitive copolymer poly(N‐tert‐butylacrylamide‐ran‐acrylamide): Synthesis and characterization

Temperature sensitive random linear and crosslinked copolymers of N‐tert‐butylacrylamide (NTBA) and acrylamide (Am) were synthesized by the solution polymerization method, using regulated dosing of comonomer Am having a higher reactivity ratio (r_Am = 1.5) than NTBA (r_NTBA = 0.5). Copolymers with varying feed ratios of NTBA and Am (80 : 20 to 20 : 80 mol %) were synthesized and characterized. For the synthesis of copolymer hydrogels, N′, N‐methylene bisacrylamide (MBA) (1.13 mol %) was used along with monomers. The effect of composition on transition properties was evaluated for the linear copolymers and their hydrogels. A definite trend was observed. The incorporation of a higher percentage of the hydrophilic comonomer Am in the structure resulted in the shifting of the transition temperature towards a higher value. The transition temperatures of the copolymers synthesized with feed compositions of 80 : 20, 70 : 30, 60 : 40, 50 : 50, 40 : 60, 30 : 70, and 20 : 80 mol % were found to be 2, 10, 19, 27, 37, 45, and 58°C, respectively. Differential scanning calorimetry (DSC) studies confirmed the formation of random copolymers. The copolymers synthesized with a monomer feed ratio of 50 : 50 with regulated dosing showed a single glass transition temperature (T_g) at 168°C, while the copolymer synthesized with full dosing of Am at the beginning of the reaction showed two T_gs, at 134 and 189°C. The copolymer samples were analyzed by Fourier transform infrared spectroscopy (FTIR) for ascertaining the composition. The composition of the copolymers followed the trend of the feed ratio, but the incorporation of NTBA in the copolymers was found to be lower than the feed ratio because of lower than quantitative yields of the reactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 672–680, 2005     

Imidazolium‐functionalized norbornene ionic liquid block copolymer and silica composite electrolyte membranes for lithium‐ion batteries

Imidazolium‐functionalized norbornene and benzene‐functionalized norbornene were synthesized and copolymerized via ring‐opening metathesis polymerization to afford a polymeric ionic liquid (PIL) block copolymers {5‐norbornene‐2‐methyl benzoate‐block ‐5‐norbornene‐2‐carboxylate‐1‐hexyl‐3‐methyl imidazolium bis[(trifluoromethyl)sulfonyl]amide [P(NPh‐b ‐NIm‐TFSI)]} with good thermal stability. On this basis, the solid electrolyte, P(NPh‐b ‐NIm‐TFSI)–lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), through blending with LiTFSI, and the nanosilica composite electrolyte, P(NPh‐b ‐NIm‐TFSI)–LiTFSI–SiO₂, through blending with LiTFSI and nanosilica, were prepared. The effects of the PILs and silica compositions on the properties, morphology, and ionic conductivity were investigated. The ionic conductivity was enhanced by an order of magnitude compared to that of polyelectrolytes with lower PIL compositions. In addition, the ionic conductivity of the nanosilica composite polyelectrolyte was obviously improved compared with that of the P(NPh‐b ‐NIm‐TFSI)–LiTFSI polyelectrolyte and increased progressively up to a maximum with increasing silica content when SiO₂ was 10 wt % or lower. The best conductivity of the P(NPh‐b ‐NIm‐TFSI)–20 wt % LiTFSI–10 wt % SiO₂ composite electrolyte with 7.7 × 10^?5 S/cm at 25 °C and 1.3 × 10^?3 S/cm at 100 °C were obtained, respectively. All of the polyelectrolytes exhibited suitable electrochemical stability windows. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44884.     

Copolymers derived from bismaleimide oligomer with active solvent

An oligomer from 4, 4′‐bis(maleimido)diphenyl methane and methylenedianiline were dissolved in active solvent N,N‐dimethyl acrylamide in a solid content up to 50–70%; the solution was poured in a sheet‐shaped module and irradiated by ⁶⁰Co with the dose from 20 to 350 kGy at room temperature. The polymerized sheet was postcured at 180°C to obtain a transparent red‐orange sheet with tensile strength above 100 MPa. The glass transition temperature before and after postcuring was around 100°C and 150–180°C, respectively. Styrene was used along with DMAA to decrease the water absorption for the copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2879–2882, 2004     

Synthesis,characterization, and thermo mechanical properties of siloxane‐modified epoxy‐based nano composite

In this study, polymer hybrid composites were synthesized by sol‐gel process. 3‐Amino‐propyltrimethoxysilane [APTMS)/γ‐Glycidoxypropyl trimethoxy‐silane (GPTMS); (4, 4′‐Methylene‐dianiline (DDM)] and 1,4‐Bis(trimethoxysilylethyl) benzene (BTB) were added to DGEBA type epoxy resin for anticipated to exhibit excellent thermal stability. Boron trifluoride monoethylamine (BF₃MEA) was used as catalyst. The structure of nanocomposites was characterized by attenuated total reflectance (ATR) and solid‐state ²⁹Si NMR which suggest EP‐APTMS‐BTB/EP‐GPTMS‐BTB possesses T³; T¹–T⁰, and T¹ structures when the BTB content was lower than 10 wt % and higher 20 wt %, respectively. BF₃MEA was proved to be an effective catalyst for the sol‐gel reaction of APTMS, but it could not promote for GPTMS. From TEM microphotographs, EP‐APTMS‐BTB (10 wt %) possesses a dense inorganic structure (particle size around 5–15 nm) compare with the loose inorganic structure of EP‐GPTM‐/BTB (10 wt %). DSC, TGA were use to analyze the thermal properties of the nanocomposites and DMA was used to analyze the dynamic mechanical properties of hybrid composites. The T_gs of all nanocomposites decreased with the increasing BTB content. A system with BTB content lower than 10 wt % showed good dynamic mechanical property and thermal stability (Td₅ increased from 336°C to 371°C, char yield increased from 27.4 to 30.2%). The structure of inorganic network affects the Td₅ and dynamic mechanical properties of composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40984.     

Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. III. Binary blends of asymmetric star block copolymer with general‐purpose polystyrene

The correlation between morphology, mechanical properties, and micromechanical deformation behavior of the blends consisting of an asymmetric styrene/butadiene star block copolymer (ST2‐S74, total styrene volume content Φ_PS = 0.74) and general‐purpose polystyrene (GPPS) was investigated using transmission electron microscopy and uniaxial tensile testing. Addition of 20 wt % of GPPS to the block copolymer resulted in a drastic reduction in strain at break, indicating the existence of critical PS lamella thickness D_c. Above D_c lamellar block copolymers displayed a transition from ductile to brittle behavior, substantiating the mechanism of thin layer yielding proposed for lamellar star block copolymers. The blends showed a variety of deformation structures ranging from classical crazelike zones to those with internal shearlike components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1208–1218, 2004     

Use of natural rubber‐g‐polystyrene as a compatibilizer in casting natural rubber/polystyrene blend films

Natural rubber/polystyrene (NR/PS) blend films with weight ratios of 70/30, 60/40, and 50/50 were prepared using polystyrene grafted natural rubber copolymers (NR‐g‐PS) as the compatibilizer. Copolymers with molar ratios of 90/10, 80/20, and 70/30 were synthesized via emulsion copolymerization using tert‐butyl hydroperoxide/tetraethylene pentamine as an initiator. The copolymers were subsequently added into the blends at 0, 5, 10, 15, 20, 25, and 30 phr. The mixtures were cast into films by the solution‐casting method using toluene as the casting solvent. Mechanical and morphological properties of the prepared films were investigated. The film prepared from 80/20 NR‐g‐PS showed higher tensile and tear strength, as well as finer domain size of the dispersed phase, than those prepared from 90/10 and 70/30 NR‐g‐PS. However, the mechanical properties of the films were decreased at high loading of the copolymers. In addition, themogravimetric analysis revealed that weight loss was decreased upon introduction of the compatibilizer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 826–831, 2005     

Porous poly(L‐lactic acid)/poly(ethylene glycol) blend films

Poly(L ‐lactic acid) (PLLA: M_w = 19.4 × 10⁴)/poly(ethylene glycol) (PEG: M_w = 400) blend films were formed by use of a solvent‐cast technique. The properties and structures of these blend films were investigated. The Young's modulus of the PLLA decreased from 1220 to 417 MPa with the addition of PEG 5 wt %, but the elongation at break increased from 19 to 126%. The melting point of PLLA linearly decreased with increases in the PEG content (i.e., pure PLLA: 172.5°C, PLLA/PEG = 60/40 wt %: 159.6°C). The PEG 20 wt % blend film had a porous structure. The pore diameter was 3–5 μm. The alkali hydrolysis rate of this blend film was accelerated due to its porous structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 965–970, 2004     

Preparation and properties of waterborne polyurethane/polyaniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid blends

A conductive poly(aniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid) [PANI‐D/H, yield: 32.2%, intrinsic viscosity ([η]): 1.39 dL/g, electrical conductivity: 7.3 S/cm] was synthesized by chemical oxidative polymerization from aniline‐dodecylbenzene sulfonic acid salt (A‐DS)/aniline‐hydrochloric acid salt (A‐HS) (6/4M ratio) in an aqueous system. Waterborne polyurethane (WBPU) dispersion obtained from isophorone diisocyanate/poly(tetramethylene oxide)glycol/dimethylol propionic acid/ethylene diamine/triethylene amine/water was used as a matrix polymer. The blend films of WBPU/PANI‐D/H with various weight ratios (99.9/0.1–25/75) were prepared by solution blending/casting. Effect of PANI‐D/H content on the mechanical property, dynamic mechanical property, hardness, electrical conductivity, and antistaticity of WBPU/PANI‐D/H blend films was investigated. The dynamic storage modulus and initial tensile modulus increased with increasing PANI‐D/H content up to 1 wt %, and then it was significantly decreased about the content. With increasing PANI‐D/H content, the glass transition temperature of soft segment (T_gs) and hard segment (T_gh) of WBPU/PANI‐D/H blend films were shifted a bit to lower the temperature. The tensile strength and hardness of WBPU/PANI‐D/H blend films increased a little with increasing PANI‐D/H content up to 0.5 wt %, and then it was dramatically decreased over the content. The elongation at break of WBPU/PANI‐D/H decreased with an increase in PANI‐D/H content. From these results, it was concluded that 0.5–1 wt % of PANI‐D/H was the critical concentration to reinforce those various properties of WBPU/PANI‐D/H blend films prepared in this study. The electrical conductivity of WBPU/ultrasonic treated PANI‐D/H (particle size: 0.7 μm) blend films prepared here increased from 4.0 × 10^?7 to 0.33 S/cm with increasing PANI‐D/H content from 0.1 to 75 wt %. The antistatic half‐life time (τ_1/2) of pure WBPU film was about 110 s. However, those of WBPU/ultrasonic treated PANI‐D/H blend films (τ_1/2: 8.2–0.1 s, and almost 0 s) were found to decrease exponentially with increasing PANI‐D/H content (0.1–9 wt %, and above 9 wt %). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 700–710, 2004     

Study of the compositional heterogeneity of ethylene/1–hexene copolymers produced over supported catalysts of different composition

Separation into narrow MWD fractions (liquid–liquid fractionation) and preparative TREF (temperature rising elution fractionation) with subsequent analysis of fractions by GPC, FTIR, and ¹³C NMR spectroscopy were used to study the comonomer distribution of ethylene/1–hexene copolymers produced over highly active supported titanium‐ and vanadium‐magnesium catalysts (TMC and VMC) and a supported zirconocene catalyst. These catalysts produce PE with different MWD: M_w/M_n values vary from 2.9 for zirconocene catalyst, 4.0 for TMC, and 15 for VMC. 1‐Hexene increases polydispersity to 25 for copolymer produced over VMC and hardly affects MWD of the copolymer produced over TMC and zirconocene catalysts. The most broad short chain branching distribution (SCBD) was found for ethylene/1–hexene copolymers produced over TMC. VMC and supported zirconocene catalyst produce copolymers with uniform profile of SCB content vs. molecular weight in spite of great differences in M_w/M_n values (22 and 2.5 respectively). TREF data showed that majority of copolymer produced over supported zirconocene catalyst was eluted at 70–90°C (about 85 wt %). In the case of VMC copolymer's fractions were eluted in the broad temperature interval (40–100°C). Accordingly, TREF data indicate a more homogeneous SCBD in copolymer, produced over supported zirconocene catalyst. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Water soluble copolymers. 54: N-isopropylacrylamide-co-acrylamide copolymers in drag reduction: Synthesis,characterization, and dilute solution behavior

Copolymers of N-isopropylacrylamide (IPAM) and acrylamide (AM) have been synthesized by free radical polymerization in deionized water using potassium persulfate as the initiator. Copolymer compositions were obtained by elemental analysis and ¹³C NMR. An r₁r₂ value of 0.99 indicates ideal copolymerization with random incorporation of the comonomers in the copolymers. Weight average molecular weights, second virial coefficients, diffusion coefficients, and average diameters were obtained via classical and quasielastic low angle laser light scattering. The molecular weights for all the copolymers and the homopolymers of IPAM and AM ranged from 2.2 × 10⁶ to 5.2 × 10⁶ g/mol. The second virial coefficients in deionized water increased with increasing acrylamide content in the copolymers. The dilute solution properties of the copolymers were studied by turbidimetry, microcalorimetry and viscometry. All the copolymers, with the exception of IPAM-40 (the copolymer synthesized with 40 mole% IPAM in the feed), showed lower critical solution temperatures below 100°C. The solution studies were performed in deionized water, 0.514 M NaCl, and 1 M urea. The properties of the IPAM copolymers were influenced by both hydrophobic associations and hydrogen bonding. In 0.2% (～7mM) sodium dodecyl sulfate, the alkyl chain of the surfactant molecules associates with the IPAM moieties on the copolymer backbone, leading to high intrinsic viscosities and the elevation of the LCST above 100°C.     

Emulsion copolymerization of vinylidene chloride and butyl methacrylate, 83:17 in mol %

Seven 35% solids, (83 : 17 in mol %), vinylidene chloride (VDC)–butyl methacrylate (BMA) copolymer latexes were prepared at 25°C using redox catalyst by batch and seeded semicontinuous emulsion copolymerization processes: one batch (G), one seeded batch (F), and five seeded semicontinuous polymerizations of five different monomer feed rates ranging from 0.27 (A) to 1.10 (E) wt %/min. All of the emulsion polymerizations gave stable latexes of almost 100% conversion with negligible coagulum and narrow particle size distributions. The kinetic studies of seeded semicontinuous polymerization A–E showed that the rates of polymerization (R_p) were controlled by the monomer addition rates (R_a), and polymerizations A–D (0.27–0.79 wt %/min) were under monomer-starved conditions; polymerization E (1.10 wt %/min) was in near-flooded condition. Significant differences were found in the physical and mechanical properties of the latex films, depending on the mode of monomer addition. Infrared spectroscopy, ¹³C solid-state NMR spectroscopy, X-ray diffraction, the T_g and T_m values by DSC, dynamic mechanical spectroscopy, and tensile strength measurement of the latex films post-heat-treated for 30 min at 70°C or aged for several months at room temperature demonstrated that batch polymerizations F and G gave copolymers of heterogeneous composition and a crystalline character. In contrast, semicontinuous polymerizations A–E gave copolymers of more uniform composition and an amorphous character.     

Synthesis,characterization, reactivity ratios by nuclear magnetic resonance spectroscopy,and application of (2,5‐Dichlorophenyl acrylate‐co‐glycidyl methacrylate) polymers as adhesives for the leather industry

2,5‐ Dichlorophenyl acrylate (DPA)‐co‐glycidyl methacrylate (GMA) polymers having five different compositions were synthesized in 1,4‐dioxane using benzoyl peroxide as a free‐radical initiator at 70 ± 0.5°C. Using ¹H‐NMR spectroscopy, the composition of the two monomers in the copolymers was calculated by comparing the integral values of the aromatic and aliphatic proton peaks. The reactivity ratios were calculated by Fineman–Ross (r₁ = 0.31 and r₂ = 1.08), Kelen–Tudos (r₁ = 0.40 and r₂ = 1.15), and extended Kelen–Tudos (r₁ = 0.39 and r₂ = 1.16) methods. The nonlinear error‐in‐variables model was used to compare the reactivity ratios. The copolymers were characterized by ¹H and proton decoupled ¹³C‐NMR spectroscopes. Gel permeation chromatography was performed for estimating the M_w and M_n and M_w/M_n of the poly(DPA) and copolymers (DPA‐co‐GMA: 09 : 91 and 50 : 50). Thermal stability of the homo‐ and copolymers was estimated using TGA [poly(DPA) > DPA‐co‐GMA (50 : 50) > DPA‐co‐GMA (09:91)], while DSC was utilized for determining the glass transition temperature. T_g increased with increased DPA content in the copolymer. The 50 : 50 mol % copolymer was chosen for curing with diethanolamine in chloroform. The cured resins were tested for the adhesive properties on leather at different temperatures (50, 90, 100, and 110°C). The resin cured at 50 °C exhibited a maximum peel strength of 1.6 N/mm, revealing a good adhesive behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1167–1174, 2006     

Reactive blends of epoxy resin (DGEBA) crosslinked by anionically polymerized polycaprolactam: Process of epoxy cure and kinetics of decomposition

The curing reactions, kinetics, morphology, and thermal stability of the reactive blends of diglycidyl ether of bisphenol‐A (DGEBA) and polycaprolactam were studied by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis. DSC studies showed that the heat of reaction (ΔH) increased when the DGEBA content was increased from 50 to 80 wt % and increased drastically above 70 wt % DGEBA content because of an increase in the extent of crosslinking. The activation energy and pre‐exponential factor of cure reactions increased drastically with an increase in the DGEBA content above 70 wt % because of a drastic increase in crosslink density. The extent of curing reaction of polycaprolactam with DGEBA is dependent on the blend composition. The nucleophilic attack on oxirane ring by amide nitrogen of polycaprolactam is a dominant curing reaction in low DGEBA compositions, and another type of curing reaction with relatively large activation energy and pre‐exponential factor also occurred, which becomes dominant when the DGEBA content reaches above 70 wt %. FTIR studies also revealed that two types of reactions do exist during the curing of polycaprolactam with DGEBA. It was observed during SEM studies that the reactive blends show multiphase system and on increasing the DGEBA content from 50 to 80 wt %, the mixing of the two phases increased. The reactive blend Ep₈₀Ca₂₀ with 80 wt % DGEBA content exhibits a single‐phase system because of better mixing of the two phases. The results of thermogravimetric analysis also indicate that the initial degradation temperature (T_i), activation energy (E), and pre‐exponential factor (Z) increased with increasing DGEBA content from 50 to 80 wt % in the reactive blends and increased drastically above 70 wt % DGEBA content due to the higher crosslink density. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 687–697, 2004