Synthesis of soluble,thermosetting polymides derived from 1,4-phenylenebis(phenylmaleic anhydride) and aromatic diamines

The dianhydride monomer 1,4-phenylenebis(phenylmaleic anhydride) was polymerized with various aromatic diamines in a one-step solution polymerization to afford high molecular weight, soluble polyimides containing backbone phenylmaleimide structures. The polymides were soluble in amide solvents, chlorinated hydrocarbons, and tetrahydrofuran at 25°C at a concentration of 15% (w/v), displayed molecular weight distributions (M_w/M_n) of 2.0–2.2 as determined by absolute GPC and showed T_g values of 240°C and above as measured by differential scanning calorimetry. In addition, polyimide thermosets were prepared from these materials by thermal cure at 350–360°C. The crosslinked polyimides displayed T_gs 20–25°C higher than their soluble precursors, and chloroform extraction indicated gel fractions ranging from 74–100% after cure. © 1994 John Wiley & Sons, Inc.     

Surface mobility and diffusion at interfaces of polystyrene in the vicinity of the glass transition

Symmetric polydisperse (M_w = 23 × 10⁴, M_w/M_n = 2.84) and monodisperse (M_w = 21 × 10⁴, M_w/M_n < 1.05) polystyrene (PS), and asymmetric polydisperse PS/poly(2,6-dimethyl 1,4-phenylene oxide) (PPO) interfaces have been bonded in the vicinity of the glass transition temperature (T_g) of PS. In a lap-shear joint geometry, strength develops in all cases with time to the fourth power, which indicates that it is diffusion controlled. Strength developing at short times at the polydisperse PS/PS interface, at 90°C, is higher than that at the monodisperse interface, at 92°C (at T_g − 13°C in both cases), presumably due to the contribution of the low molecular weight species. The decrease of strength at the PS/PPO interface when the bonding temperature decreases from 113 to 70°C, i.e., from T_g + 10°C to T_g − 33°C of the bulk PS, indicates a high molecular mobility at the surface as compared to that in the bulk, and can be expressed by a classical diffusion equation, which is valid above T_g (of the surface layer). © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 567–572, 1998     

Living/controlled cationic cyclopolymerization of divinyl ether with a cyclic acetal moiety: Synthesis of poly(vinyl ether)s with high glass transition temperature based on incorporation of cyclized main chain and cyclic side chains

Cationic cyclopolymerization of 2‐methyl‐5,5‐bis(vinyloxymethyl)‐1,3‐dioxane ( 1 ), a divinyl ether with a cyclic acetal group, was investigated with the HCl/ZnCl₂ initiating system in toluene and methylene chloride at ?30 °C. The reaction proceeded quantitatively to give gel‐free, soluble polymers in organic solvents. The number‐average molecular weight (M_n) of the polymers increased in direct proportion to monomer conversion, and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that the polymerization proceeded in living/controlled manner. The contents of the unreacted vinyl groups in the produced soluble polymers were less than ～3 mol %, and therefore, the degree of cyclization was determined to be ～97%. In contrast, the pendant cyclic acetal groups remained intact in the polymers under the present cationic polymerization conditions. These facts show that cyclopolymerization of 1 almost exclusively occurred and the poly(vinyl ether)s with the cyclized repeating units and cyclic pendant acetal rings were obtained. Glass transition temperature (T_g) and thermal decomposition temperature (T_d) of poly( 1 ) (M_n = 7870, M_w/M_n = 1.57) were found to be 166 and 338 °C, respectively, indicating that poly( 1 ) had high T_g and high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 952–958, 2010     

Synthesis of poly(2‐furyloxirane) with high molecular weight and improved regioregularity using macrocyclic ether as a cocatalyst to potassium tert‐butoxide

2‐Furyloxirane (FO), a monomer usually obtained from a nonpetroleum route, was prepared from the epoxidation reaction of furfural and trimethylsulfonium chloride. About 200–300 g FO can be obtained in each preparation process. Although anionic polymerization of FO generally gives low‐ molecular‐weight polymers even after long periods of polymerization, the reaction was greatly improved when macrocyclic ether was used as a cocatalyst to potassium tert‐butoxide. When 18‐crown‐6 was used as a cocatalyst, poly(2‐furyloxirane) (PFO) with a number‐average molecular weight (M_n) of 41.5 kg/mol and a polydispersity index of 1.3 was obtained at 94% yield after polymerization at 40 °C for 72 h. The PFO obtained contained a 61.7% head‐to‐tail (H‐T) structure in the absence of the macrocyclic ether, and it reached 70.6% when cryptand[2,2,2] was used as a cocatalyst. PFO with higher regioregular structures showed improved thermal properties. For PFO with M_n of around 20.0 kg/mol, its glass transition temperature (T_g) increased from ?3 to 6 °C when the H‐T content was increased from 61.7 to 70.6%. Raising the M_n of PFO also raised T_g. For PFO with 68.9% H‐T structure, its T_g could reach 7 °C when M_n was increased to 40 kg/mol. This study shows two effective ways to improve the thermal and mechanical performances of the polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Polymerization of N-(p-aminobenzoyl)caprolactam: Block and alternating copolymers of aromatic and aliphatic polyamides

The polymerization behavior of N-(p-aminobenzoyl)caprolactam was studied. It was found that polymerization could proceed by either elimination of caprolactam or by ring opening. Polymers prepared at temperatures above 200°C showed a greater tendency for ring opening to produce alternating aromatic/aliphatic copolymers than did polymers prepared at lower temperatures. Block copolymers of poly(p-benzamide) and nylon 6 were prepared by a two-stage hydrolytic polymerization process or by anionic polymerization at temperatures > 200°C. Polymer microstructures were determined using ¹³C-NMR spectroscopy by comparison with homopolymers and model alternating copolymers. The alternating copolymer prepared by condensation of N-(p-aminobenzoyl)-6-caproic acid showed a melting transition at 300–305°C in the DSC and a T_g in subsequent heating cycles of 116–119°C. Copolymers made with the two-stage process were rich in p-benzamide sequences and showed no T_g or T_m below 400°C. Copolymer made with NaH was rich in nylon 6 units, showed a T_m of 175–180°C and a T_g of 80–81°C, and was homogeneous in both the melt and solid.     

Living cationic polymerization of 2‐adamantyl vinyl ether

Living cationic polymerization of 2‐adamantyl vinyl ether (2‐vinyloxytricyclo[3.3.1.1]^3,7decane; 2‐AdVE) was achieved with the CH₃CH(OiBu)OCOCH₃/ethylaluminum sesquichloride/ethyl acetate [CH₃CH(OiBu)OCOCH₃/Et_1.5AlCl_1.5/CH₃COOEt] initiating system in toluene at 0 °C. The number‐average molecular weights (M_n's) of the obtained poly(2‐AdVE)s increased in direct proportion to monomer conversion and produced the polymers with narrow molecular weight distributions (MWDs) (M_w/M_n = ～1.1). When a second monomer feed was added to the almost polymerized reaction mixture, the added monomer was completely consumed and the M_n's of the polymers showed a direct increase against conversion of the added monomer. Block and statistical copolymerization of 2‐AdVE with n‐butyl vinyl ether (CH₂?CH? O? CH₂ CH₂CH₂CH₃; NBVE) were possible via living process based on the same initiating system to give the corresponding copolymers with narrow MWDs. Grass transition temperature (T_g) and thermal decomposition temperature (T_d) of the poly(2‐AdVE) (e.g., M_n = 22,000, M_w/M_n = 1.17) were 178 and 323 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1629–1637, 2008     

Syntheses and properties of poly(diethyl vinylphosphonate) initiated by lanthanide tris(borohydride) complexes: Polymerization controllability and mechanism

Polymerization of diethyl vinylphosphonate (DEVP) is achieved by using lanthanide tris(borohydride) complexes, Ln(BH₄)₃(THF)₃ (Ln = Y, La, Nd, Sm, Gd, Dy, Lu) as an initiator. The characteristics and mechanism of polymerization as well as the properties of the resulting poly(diethyl vinylphophonate)s (PDEVPs) are studied. The effects of the lanthanide elements, the molar ratios of monomer to initiator ([M]/[ln]), reaction temperature and time on polymerization have been investigated in detail. The optimized polymerization conditions are 40 °C, 1 h in bulk with [M]/[ln] = 300. The kinetic study indicates that the polymerization of DEVP undergoes a controlled manner as the molecular weights (MWs) of PDEVPs increase with monomer conversion linearly maintaining moderate MW distribution (1.7–1.9). Additionally, a coordination anionic polymerization mechanism is proved by end‐group analysis with ESI mass and ¹H NMR spectroscopy. The obtained PDEVPs have low glass transition temperature (T_g = ?62 °C) and high thermal decomposition temperature (T_d > 300 °C) determined by differential scanning calorimetry and thermogravimetric analysis respectively. The thermosensitive behavior of PDEVP is characterized by evaluating the lower critical solution temperature of PDEVP in water by ultraviolet transmittance. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2409–2415     

Synthesis and polymerization of N‐(4‐tetrahydropyranyl‐oxyphenyl)maleimide

N‐(4‐Tetrahydropyranyl‐oxy‐phenyl)maleimide (THPMI) was prepared and polymerized by radical or anionic initiators. THPMI could be polymerized by 2,2′‐azobis(isobutyronitrile) (AIBN) and potassium tert‐butoxide. Radical polymers (poly(THPMI)r) were obtained in 15–50% yields for AIBN in THF at 65°C after 2–5 h. The yield of anionic polymers (poly(THPMI)a) obtained from potassium tert‐butoxide in THF at 0°C after 20 h was 91%. The molecular weights of poly(THPMI)r and poly(THPMI)a were M_n = 2750–3300 (M_w/M_n = 1.2–3.3) and M_n = 11300 (M_w/M_n = 6.0), respectively. The difference in molecular weights of the polymers was due to the differences in the termination mechanism of polymerization and the solubility of these polymers in THF. The thermal decomposition temperatures were 205 and 365°C. The first decomposition step was based on elimination of the tetrahydropyranyl group from the poly(THPMI). Positive image patterns were obtained by chemical amplification of positive photoresist composed of poly(THPMI) and 4‐morpholinophenyl diazonium trifluoromethanesulfonate used as an acid generator. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 341–347, 1999     

Water-soluble silicon containing polymer resist

Poly(divinylsiloxyethylene glycol), which consists of alternating oligo(ethylene glycol)s (MW = 300) and divinylsiloxanes were prepared by a polycondensation reaction (M_n = 6500–9300, M_w/M_n = 2.01–2.27). The obtained polymer (PVSE300) showed a lower critical solution temperature (LCST) at 10.5°C, meaning that the polymer was soluble in water below the LCST. The glass transition temperature (T_g) and onset temperature of degradation (T_d) of the PVSE300 were −72.5 and +317.5°C, respectively. The hydrolytic stability of the PVSE300 in aqueous media was also examined and it was found that PVSE300 was fairly stable in cold water. The lithographic characteristics of PVSE300 were examined against UV and electron-beam (EB) exposure and it was found that the PVSE300 film showed a negative character when developed by cold water. The photosensitivity parameter, Dg⁵⁰, which denotes the dose at half remaining film thickness after development, against EB exposure was extremely high (1.0 μC/cm²) when a probe current and an accelerating voltage was 100 pA and 20 kV, respectively. A high durability for O₂ reactive ion etching (O₂ RIE) was also observed. The characteristics of PVSE300 against photoirradiation were also examined. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2827–2833, 1997     

Alkoxyamine‐mediated “living” radical polymerization: MS investigation of the early stages of styrene polymerization initiated by cumyl‐TEISO

A new series of 1,1,3,3‐tetraethylisoindoline‐2‐oxyl (TEISO)‐based alkoxyamines was prepared. The half‐lives for thermal dissociation indicated that the most sterically congested cumyl‐TEISO alkoxymine had the greatest potential as an initiator for the polymerization of monomers at lower temperatures. The polymerization of styrene at 110 °C gave a linear evolution of M_n with conversion in the early stages. Further evidence for the “living” nature was given by the polydispersities of the polymers that remained low (M_w/M_n = 1.13–1.27) throughout the polymerization (up to 80% conversion). No polymer was formed for the styrene system in a reasonable time below 100 °C. High‐performance liquid chromatographic/mass spectrometric investigations of the distribution of trapped oligomers containing one to nine monomer units formed at 60 °C revealed that the trapping of oligomeric cumyl–styryl radicals by TEISO is irreversible at this temperature. Methyl methacrylate polymerized with cumyl‐TEISO at 60–70 °C, although the initial high rates of polymerization soon decreased to zero at low conversions (10–15%), and the high polydispersities (M_w/M_n = 1.42–1.73) indicated significant side reactions. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1232–1241, 2001     

Novel,biodegradable, functional poly(ester‐carbonate)s by copolymerization of trans‐4‐hydroxy‐L‐proline with cyclic carbonate bearing a pendent carboxylic group

Water‐soluble poly(ester‐carbonate) having pendent amino and carboxylic groups on the main‐chain carbon is reported for the first time. This article describes the melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) with 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) at a wide range of molar fractions. The influence of reaction conditions such as catalyst concentration, polymerization time, and temperature on the number average molecular weight (M_n) and molecular weight distribution (M_w/M_n) of the copolymers was investigated. The polymerizations were carried out in bulk at 110 °C with 3 wt % stannous octoate as a catalyst for 16 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR, differential scanning calorimetry, and gel permeation chromatography. The copolymers synthesized exhibited moderate molecular weights (M_n = 6000–14,700 g mol^?1) with reasonable molecular weight distributions (M_w/M_n = 1.11–2.23). The values of the glass‐transition temperature (T_g) of the copolymers depended on the molar fractions of cyclic carbonate. When the MBC content decreased from 76 to 12 mol %, the T_g increased from 16 to 48 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐MBC) T_g and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐MBC)s was evaluated from weight‐loss measurements and the change of M_n and M_w/M_n. Debenzylation of 3 by catalytic hydrogenation led to the corresponding linear poly(ester‐carbonate), 4 , with pendent amino and carboxylic groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2303–2312, 2004     

Precision synthesis of (1→6)-α-D-glucopyranan by cationic ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-allyl-β-D-glucopyranose

The ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-allyl-β-D-glucopyranose ( 2 ) has been carried out using various cationic initiators. For the condition of [ 2 ]/[BF₃·OEt₂] = 20 at −15°C for 90 h, the polymer yield, M_w and M_w/M_n of the polymer obtained were 79%, 215,600 and 3.45, respectively. In order to study the living characteristic of the polymerization of 2 , the cationic ring-opening bulk polymerization initiated by trimethylsilyl trifluoromethanesulfonate (TMSOTf) was carried out under the condition of [ 2 ]/[TMSOTf] = 1000 at −15 °C. The M_w value increased in proportion to conversion until c.a. 30% and below. The M_w/M_ns of resulting polymers were very narrow, e.g., the M_w/M_n value was 1.2 and below, which was smaller than that for the solution polymerization using BF₃·OEt₂. These results indicated that the ring-opening bulk polymerization of 2 using TMSOTf was living-like.     

Effect of Molecular Weight on Enthalpy Relaxation in Syndiotactic Poly(Methyl-Methacrylate)

The structural relaxation behaviour of narrow fractions (M_w/M_n < 1.1) of syndiotactic poly(methyl methacrylate) with molecular masses ranging from 2,000 to 200,000 Daltons have been studied by DSC with two classical procedures, namely: the rate of cooling and the isothermal approaches. The apparent activation energy (Δh*) of enthalpy relaxation was evaluated from the dependence of the glass transition temperature on the cooling rate while a comparison of the apparent relaxation rates was appraised from the enthalpy loss by annealing the different samples at the same level of undercooling (T_a = T_g − 10 °C). As expected, the increase of molecular weights gives rise to both a continuous increase of Δh* and a decrease of the apparent isothermal relaxation rate. More interestingly, both Δh* and the apparent isothermal relaxation rate showed abrupt changes around the syndiotactic PMMA entanglement mass (M_e ).     

Synthesis of bio-based poly(methacrylates) using SG1-containing amphiphilic macroinitiators by nitroxide mediated miniemulsion polymerization

SG1-based amphiphilic macroinitiators were synthesized from oligoethylene glycol methyl ether methacrylate and 10 mol% acrylonitrile or styrene (as the controlling comonomer) to conduct the nitroxide mediated polymerization of bio-based methacrylic monomers (isobornyl methacrylate (IBOMA) and C13 alkyl methacrylate (C13MA)) in miniemulsion. The effect of the addition of surfactant (DOWFAX 8390), co-stabilizer (n-hexadecane) and different reaction temperatures (80, 90 and 100°C) on polymerization kinetics was studied. We found that the NMP of IBOMA/C13MA using amphiphilic macroalkoxyamines were most effective during miniemulsion polymerization (linear trend of M_n versus conversion and high latex stability) in presence of 2 wt% surfactant and 0.8 wt% co-stabilizer (relative to monomer) at 90°C. The effect of surfactant, co-stabilizer and temperature on particle size during the polymerization was studied and suggested a decrease in initial particle size with the addition of surfactant and co-stabilizer. Finally, the thermal properties of IBOMA/C13MA polymers, prepared by amphiphilic macroinitiators, were examined thoroughly, indicating a T_g in the range of −44°C < T_g < 109°C.     

Living anionic polymerization of ethylphenylketene: A novel approach to well‐defined polyester synthesis

A living polymerization of ethylphenylketene (EPK) was accomplished. When polymerization of EPK was carried out with butyllithium as an initiator in tetrahydrofuran (THF) at −20 °C, EPK was completely consumed within 5 min, and the corresponding polyester with narrow molecular weight distribution (M_w /M_n ∼ 1.1) was obtained almost quantitatively. Kinetic study of the polymerization at −78 °C revealed that conversion of EPK agreed with the first‐order kinetic equation, and that M_n of the polymer increased in virtually direct proportion to the conversion. Along with these results, successful results in postpolymerization at −20 °C strongly supported living mechanism of the present polymerization. Further, lithium alkoxides having a methoxy group, styryl moiety, and nitroxyl radical, also successfully initiated polymerization of EPK to afford the corresponding polymers having functional initiating ends. In the polymerization with varying feed ratio [EPK]₀/[initiator]₀, the linear relationship between the feed ratio and M_n of the obtained polymer was observed, while maintaining narrow M_w /M_n. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1073–1082, 2000     

Synthesis of thermotropic LCPs using p‐methoxycarbonyloxy aromatic acids

4‐Methoxycarbonyloxybenzoic acid (MCOBA) and 6‐methoxycarbonyloxy‐2‐naphthoic acid (MCONA) were synthesized as new monomers to replace 4‐acetoxybenzoic acid (ABA) and 6‐acetoxy‐2‐naphthoic acid (ANA) in the synthesis of liquid crystal polymers. MCOBA and MCONA (73 : 27, mol : mol) were reacted at temperatures ranging from 220 to 325°C in bulk. The copolymer (M_w = 14,200) has a T_g (90°C) and a T_m (249°C). The MCOBA/MCONA copolymer is lighter in color than the ABA/ANA copolymer. During the copolymerization, six by‐products were collected, isolated, and analyzed, and their formation was investigated. The copolymerization rate was studied by the measurement of evolved carbon dioxide. The polymerization of MCOBA and MCONA is cleaner and faster than the polymerization of ABA and ANA. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1703–1707, 1999     

Thermal and mechanical properties of random copolymers of diisopropyl fumarate with 1‐adamantyl and bornyl acrylates with high glass transition temperatures

We report the thermal, optical, and mechanical properties of random copolymers produced by radical copolymerizations of diisopropyl fumarate (DiPF) with 1‐adamantyl acrylate (AdA) and bornyl acrylate (BoA). The effects of a methylene spacer included in the main chain and bulky ester alkyl groups in the side chain on the copolymer properties are discussed. The produced copolymers are characterized by NMR and UV–vis spectroscopies, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). The copolymerization rate and the molecular weight of the copolymers increase with an increase in the acrylate content in feed during the copolymerization (M_w = 25–110 × 10³). The onset temperature of decomposition (T_d5) and the glass transition temperature (T_g) of the copolymers also increase according to the content of the acrylate units (T_d5 = 296–329 °C and 281–322 °C, T_g = 80–133 °C and 91–106 °C for the copolymers of DiPF with AdA and BoA, respectively). Transparent and flexible copolymer films are obtained by a casting method and their optical properties such as transparency and refractive indices are investigated (n_D = 1.478–1.479). The viscoelastic data of the copolymers are collected by DMA measurements under temperature control. The storage modulus decreases at a temperature region over the T_g value of the copolymers, depending on the structure and amount of the acrylate units. The sequence structure of the copolymers is analyzed based on monomer reactivity ratios and composition in order to discuss the copolymer properties related to chain rigidity and sequence length distribution. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 288–296     

Molecular weight distribution and stereoregularity of polypropylenes produced with VCl4–AlEt2Cl catalyst

Dependences of the molecular weight distribution and stereochemical regulation of the polypropylenes produced with VCl₄–AlEt₂Cl catalyst on the polymerization temperature were examined. The molecular weight distributions of the polymers obtained at temperatures below ?40°C were unimodal and narrow (M _w/M _n ≤ 2). The molecular weight distributions obtained at higher temperatures (above ?21°C) were bimodal with one narrow distribution and one wide one (M _w/M _n > 2), and the polymer fraction of the wide distribution increased with the polymerization temperature. The fractional amount of ? (CH₂)₂? groups in the polymers, which corresponds to tail-to-tail linkage of two propylene units, increased to a maximum at ?21°C followed by a gradual decrease with the polymerization temperature. The production of isotactic polymers was confirmed at temperatures above ?21°C. From these data, it is concluded that only the homogeneous form of the catalyst system is responsible for the polymerization at temperatures below about ?21°C while the heterogeneous form appears and catalyzes the polymerization together with the homogeneous one at temperatures above ?21°C.     

Cyclopolymerization of amine-linked diacrylate monomers

New diacrylate monomers for cyclopolymerization were synthesized from the reaction of ethyl α-chloromethylacrylate (ECMA) and t-butyl α-bromomethyl acrylate (TBBr) with aniline, adamantyl amine, t-butyl amine, cyanamide, and 4-tetradecyl aniline in yields of ca. 50–70%. Bulk and solution polymerizations with azobisisobutyronitrile (AIBN) at 60–85°C gave soluble cyclopolymers with M_n and M_w ranging from 10,000–30,000 and 12,000–40,000, respectively. The ECMA–cyanamide derivative only gave crosslinked polymers. ¹H and ¹³C solution NMR indicated high cyclization efficiency (>93%). A prototype NLO polymer was synthesized from the reaction of the TBBr–aniline cyclopolymer with tetracyanoethylene. The p-hydroxyaniline derivative of ECMA was synthesized and used for further derivatizations; for example, the benzoate ester was made and polymerized (M_n = 21,260 and M_w = 40,317). The ester groups of the TBBrndash;aniline polymer were hydrolyzed completely to give a polymer with both acid and base moieties. DSC thermograms showed glass transitions of 132°C for the ECMA–aniline derivative, 192°C for the ECMA–adamantyl derivative, 53°C for the TBBr–tetradecylaniline derivative, and 120° for the ECMA–p-benzoylaniline derivative. The ECMA–t-butyl amine polymer showed no obvious T_g. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2111–2121, 1997     

Synthesis,characterization and properties of a soluble polymer with a poly(phenylenevinylene) structure

Soluble poly(2,5-dialkoxy-1,4-phenylenevinylene) has been prepared via Stille coupling reaction between 2,5-dialkoxy-1,4-diiodobenzene and E-1,2-bis(tributylstannyl)-ethene in the presence of palladium complexes. Characterization of this material by means of ¹H and ¹³C nuclear magnetic resonance (NMR), ultraviolet/visible (UV/VIS) and infrared (IR) spectra is described. Molecular weights, determined by means of gelpermeation chromatography (GPC) analysis and referred to standard polystyrene, were in the range number-average molecular weights M _n = 2061–2544 and weight-average molecular weights M _w = 3347–3878. X-ray diffraction (XRD) analysis of the polymer showed semicrystalline structure. T_g = 57°C, transition to a stable smectic mesophase at 115°C and clearing point at 210°C were revealed by differential scanning calorimetry analysis, optical microscopy observation and XRD of the annealed polymer.