Functional polymers and sequential copolymers by phase-transfer catalysis. 15. Thermotropic copolyethers based on 4,4′-dihydroxybiphenyl,bisphenol a and 1,9-dibromononane

Thermotropic liquid crystalline (LC) copolyethers have been synthesized from 1,9-dibromononane, a nonmesogenic bisphenol (4,4′-isopropylidenediphenol [BPA]) and a mesogenic bisphenol (4,4′-dihydroxybiphenyl [HB]) by a two-phase (organic solvent—aqueous NaOH) phase-transfer catalyzed polyetherification. LC polyethers were obtained for copolymers containing as much as 70 mol % BPA. Optical polarizing microscopy and DSC have revealed smectic mesomorphism for all the copolyethers. The influence of both copolymer composition and microstructural changes, including the nature of the chain ends, upon the mesomorphic properties of these copolyethers have been discussed.     

Functional polymers and sequential copolymers by phase transfer catalysis. 25. Transformation of a monotropic mesophase into an enantiotropic one by increasing the molecular weight of the polymer and by copolymerization

The influence of molecular weight on thermal transitions and on the thermodynamic parameters was studied for two polymers based on 4,4′-dihydroxy-α-methylstilbene with either 1,9-dibromononane (HMS-C9 polyethers) or 1,11-dibromoundecane (HMS-C11 polyethers). HMS-C9 polyethers present an enantiotropic nematic mesophase over the entire range of molecular weights and a monotropic smectic mesophase for polymers of number average molecular weights higher than 17,000. The low molecular weight HMS-C11 polyethers are only crystalline. On increasing their molecular weight, the polymers become monotropic nematics, and at higher molecular weights, enantiotropic nematics. Up to a composition containing as little as 20 mol % nonane structural units, the random copolyethers based on 1,9-dibromononane, 1,11-dibromoundecane, and 4,4′-dihydroxy-α-methylstilbene (HMS-C9/11 copolyethers) exhibit on cooling a phase diagram resembling that of HMS-C9 polyether. HMS-C9/11 containing about a 1/1 mole ratio between the two spacers presents both smectic and nematic enantiotropic mesophases. These results suggest that the phase diagram of random liquid crystalline copolymers is controlled by the shorter spacer. The thermodynamic parameters of isotropization for both polyethers and copolyethers are compared and suggest that copolymerization does not significantly decrease the degree of order of the mesogenic units in the mesomorphic phase.     

Nematic conformation of oxyethylene spacers involved in main-chain liquid crystals

²HNMR measurements were performed on main-chain dimer and polymer liquid crystals (LC) having oxyethylene (OE) spacers -(OCH₂CH₂)_xO-(x=2, 3). The orientational as well as conformational characteristics of these molecules have been investigated in bulk and in a nematic solution. The OE spacer was found to take spatial arrangements characteristics of the nematic phase. The nematic conformation of the spacer remains nearly invariant over a wide range of temperature and concentration. In these analyses, the ratio of the deuterium quadrupolar splittings Δν/Δν^R (Δν: spacer and Δν^R: mesogenic unit) provided an important information regarding the spatial configuration of molecules in the LC state. The results obtained in this study are consistent with our previous conclusion drawn on a series of main-chain LC oligomers and polymers comprising n-alkane spacers -O(CH₂)_nO- (n=9, 10).     

Functional polymers and sequential copolymers by phase-transfer catalysis. 16. Influence of sequence distribution on the mesomorphic properties of thermotropic copolyethers containing 4,4′-dihydroxybiphenyl

Random and alternating thermotropic liquid-crystalline copolyethers have been synthesized from 4,4′-dihydroxybiphenyl and a 1/1 mol ratio of 1,5-dibromopentane and α,ω-dibromoalkanes by a two-phase (organic solvent-aqueous NaOH) phase-transfer-catalyzed polyetherification. Random copolyethers were prepared from α,ω-dibromoalkanes having six to twelve methylene units. Their phase behavior was compared with those of the perfectly alternating copolyethers containing five methylene units in one spacer and eight, nine, or eleven methylene units in the other, respectively. An odd-even dependence in thermal transitions has been observed in both oligomeric systems. In all cases, alternating copolyethers, even though comparatively lower in molecular weight, have given rise to higher melting and isotropization temperatures. Since the increase in the melting temperature is larger than the increase in the isotropization temperature, the thermal stability range of the mesophase has narrowed for alternating copolyethers with respect to their random copolyether counterparts.     

Ionic conductivity and compatibility studies of blends of poly(methyl methacrylate) and poly(propylene glycol) complexed with LICF3SO3

Stable to atmospheric moisture, adhesive and transparent polymer electrolytes have been prepared by blending poly(methyl methacrylate) (PMMA) with poly(propylene glycol)-425/LiCF₃SO₃ complexes. The blending of the polymers has been achieved by a method developed in our laboratory: free radical polymerization of methylmethacrylate in the polyether/salt matrix. A series of polymer blend complexes varying in PMMA content (up to 20% by weight) and oxygen/metal ratios (25, 16, and 8) have been synthesized and their properties studied. All the samples prepared in this study were found to be optically clear unlike the higher molecular weight poly(propylene glycol)-2000 (PPG-2000) system which required a minimum salt concentration to compatibilize a specific amount of PMMA with PPG. The mechanisms by which the salt holds the otherwise incompatible polymers together in a single phase have been investigated by FT-IR. Our studies show a weak coupling of the ether oxygens in the PPG with the ester groups of the PMMA through the lithium cations. Discrete changes has been observed in the FT-IR spectrum of PMMA when doped with the lithium salt hitherto unnoticed with other dopants. Gel permeation chromatography results of the PMMA samples isolated from the solid electrolytes indicate the molecular weight to vary between 43000 and 121000 with relatively narrow distributions, 1.6?2.0. The ionic conductivities of the polymer blend electrolytes were fairly high (10^?5 S/cm) at room temperature. The PMMA neither significantly influenced the T_g of the blend complexes nor effected the ionic conductivities drastically. The ionic conductivity as a function of temperature followed the empirical Vogel-Tammann-Fulcher equation. The blending of PMMA with PPG/LiCF₃SO₃ complexes was found to impart good adhesiveness to the solid electrolytes while making them stable to atmospheric moisture. © 1992 John Wiley & Sons, Inc.     

Segmented polyethylene oxides: A new class of polyethers prepared via melt transetherification

Several segmented polyethylene oxides (SPEOs) were prepared by a melt-transetherification process using 1,4-bis(methoxymethyl)-2,3,5,6-tetramethylbenzene and polyethylene glycols (PEGs) of different molecular weights (di-, tri-, and tetraethylene glycols and PEGs of molecular weights 300, 600, 1000, 1500, and 3400) as the monomers. The effect of polymerization temperature (185 and 150 °C) on the molecular weight of SPEOs was studied, and it was shown that the molecular weight is larger at a higher polymerization temperature. The reversal of the polycondensation (transetherification) equilibrium by treatment of the polyethers with excess methanol transformed them completely into the starting monomers. The analysis of the degraded products by mass and NMR spectroscopies revealed that side reactions, such as the self-condensation of diols, are insignificant. The polymers containing shorter PEG spacers are amorphous, whereas the ones with longer PEG spacers are semicrystalline. The glass-transition temperature (T_g) of the SPEOs decreased with increases in the spacer length and attained the value of PEO at PEG-600, whereas the melting transition (T_m), crystallization temperature (T_c), and their enthalpies of transition, (ΔH_m) and (ΔH_c), increased with increases in the spacer length. The introduction of “molecular kinks” into SPEOs by the use of another monomer, 1,3-bis(methoxymethyl)-2,4,5,6-tetramethylbenzene, surprisingly, showed little effect on their thermal properties. A “branched-PEO” analogue, containing pendant oligoethyleneoxy units, was also prepared, and its thermal properties were compared with its linear analogue. Preliminary ionic conductance measurements showed that some of these SPEOs could serve as potential candidates for solid polymer–electrolyte applications. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1615–1628, 2001     

Poly(phenyl methacrylate) and poly(1‐naphthyl methacrylate) prepared in microemulsions

Phenyl methacrylate and 1‐naphthyl methacrylate were polymerized in microemulsions using stearyltrimethylammonium chloride, cetyltrimethylammonium bromide, and a mixture of nonionic Triton surfactants to form latexes that were 20–30 nm in diameter. A temperature of 70 °C was needed to obtain polymers using thermal initiation. The tacticities of poly(phenyl methacrylate) (PPhMA) (55% rr) and poly(1‐naphthyl methacrylate) (P‐1‐NM) (47% rr) were the same as those of the polymers prepared in toluene solutions. The weight average molecular weights were 1 × 10⁶ and 5 × 10⁵ g/mol for PPhMA and P‐1‐NM prepared in microemulsions with very broad distributions. PPhMA samples from microemulsions and solution had the same T_g = 127 °C. P‐1‐NM from microemulsions had T_g = 145–147 °C compared with T_g = 142 °C for P‐1‐NM from solution. The molecular weights and the glass‐transition temperatures of both PPhMA and P‐1‐NM from microemulsions are substantially higher than any previously reported. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 519–524, 2001     

Functional polymers and sequential copolymers by phase transfer catalysis. XXVIII. Synthesis and characterization of alternating block copolymers and polyformals of polyisobutylene and aromatic polyether sulfone

Alternating—i.e., -(A-B)_n- type—block copolymers of polyisobutylene (PIB) and aromatic polyether sulfone (PSU) have been prepared by phase transfer catalyzed Williamson polyetherification of α,ω-di(phenol)PIB with α,ω-di(chloroallyl)- or -(bromobenzyl)PSU. Block copolymers of the two prepolymers were also synthesized by the phase transfer catalyzed polyetherification of methylene chloride with α,ω-di(phenol)PIB and α,ω-di(phenol)PSU (bisphenol-A-terminated PSU). This method leads to -[(A)_x-(B)_y]_n- block copolymers with formal linkages between segments. At sufficiently high segment lengths, both types of block copolymers exhibit two distinct T_gs, indicating phase separation into rubbery PIB and glassy PSU domains.     

Functional polymers and sequential copolymers by phase transfer catalysis. XIX. Thermotropic polythioethers and copolythioethers based on 4,4′-dithiolbiphenyl

Thermotropic liquid crystalline (LC) polythioethers and copolythioethers have been synthesized from 4,4′-dithiolbiphenyl (TB) and α,ω-dibromoalkanes having between two and twelve methylene units. Copolythioethers were prepared from TB and a 1:1 mol/mol ratio of 1,5-dibromopentane and α,ω-dibromoalkanes having nine to twelve methylene units. Peculiarities of the phase-transfer catalyzed (PTC) polyetherification reaction in the preparation of these polymers have led to aliphatic-ether structural units. This side reaction has been explained by a possible neighboring group effect with sulfur, through sulfonium formation, and is consistent with a mechanism previously proposed in PTC polyetherifications. While not significantly enhancing solubility, the copolymeric nature of these polymers have led to lower melting and isotropization temperatures with broad mesophase thermal stability ranges. Lastly, unique spherulitic textures resembling higher-ordered smectic mesophases have been observed in all the prepared polymers.     

NOTE: Synthesis and Characterization of a Poly(acrylamide) with Pendant 1,4-piperazine-2,5-dione Moieties via Post-polymerization Cyclization

A poly(acrylamide) was synthesized from N ^α -Boc-N ^? -acrolyl-l-lysylglycine methyl ester via radical polymerization. This polymer typically had Mn ～ 100,000 g/mol, Mw ～ 300,000 g/mol, and a T_g of 93°C. Removal of Boc with TFA and cyclization with DABCO? in DMSO at 65°C afforded a soluble piperazinedione-containing polymer that had a T_g of 157°C and thermal stability up to 300°C. These results demonstrate a viable and efficient synthetic route to piperazinedione-containing polyacrylamides of high molecular weight. Related polymers that incorporate substituted indane moieties could be useful high T_g materials for fabrication of LC and NLO devices.     

Functional polymers and sequential copolymers by phase transfer catalysis. 24. The influence of molecular weight on the thermotropic properties of a random copolyether based on 1,5-dibromopentane, 1,7-dibromoheptane,and 4,4′-dihydroxy-α-methylstilbene

The influence of molecular weight on thermal transitions and on their thermodynamic parameters is discussed for a random thermotropic liquid crystalline copolyether based on the reaction of a 1:1 molar mixture of 1,5-dibromopentane and 1,7-dibromoheptane with 4,4′-dihydroxy-α-methylstilbene. Optimum phase transfer catalyzed polyetherification reaction conditions were established for the synthesis of polymers containing bromoalkane chain ends only over a wide variety of molecular weights. All these copolyethers present a crystalline and an enantiotropic nematic mesophase over the entire range of molecular weights studied. Both the thermal transitions and their thermodynamic parameters are strongly molecular weight-dependent up to M _n = 10,000–12,000, after which they remain constant. The enthalpies and entropies of isotropization of the copolyethers are higher than those of melting. This is in contrast to the same thermodynamic parameters of the corresponding homopolyethers. The enthalpies and entropies of isotropization of both homopolymers and copolymers present similar values, suggesting that copolymerization does decrease the degree of order in the crystalline phase but does not significantly change the alignment degree of the mesogenic units in the nematic mesophase.     

Synthesis,characterization, and crosslinking of novel stars comprising eight poly(isobutylene‐azeotropic‐styrene) copolymer arms with allyl or hydroxyl termini. I. Living azeotropic copolymerization of isobutylene and styrene

The overall objective of this research is the creation of novel star polymers consisting of well‐defined stable cores out of which radiate multiple poly(isobutylene‐co‐styrene) [P(IB‐co‐St)] arms whose glass‐transition temperature (T_g) can be controlled over a wide range (?73 to +100 °C) and whose arm termini are fitted with multipurpose (e.g., crosslinkable) functionalities. The first article of this series relates the synthesis and characterization of azeotropic IB/St copolymers [P(IB‐aze‐St)], which are to be subsequently used as end‐functional arms of the target stars. The P(IB‐aze‐St)s are models for statistical IB/St copolymers. The azeotropic composition is 21/79 (mol/mol) IB/St, and NMR, Fourier transform infrared, and gel permeation chromatography techniques demonstrate copolymer compositional homogeneity over the 12–96% conversion range. Conditions were developed for living azeotropic IB/St copolymerization. The livingness of the azeotropic copolymerization was proven by kinetic investigations. P(IB‐aze‐St)s with number‐average molecular weights of up to 24,000 g/mol and polydispersity indices (weight‐average molecular weight/number‐average molecular weight) less than 1.5 were prepared. The copolymerization reactivity ratios were determined: r_IB = 3.41 ± 0.23 and r_St = 1.40 ± 0.26. The effect of the P(IB‐aze‐St) molecular weight on T_g was studied by DSC. T_g increases linearly with the number‐average molecular weight and reaches a plateau at 62 °C at 24,000 g/mol. The heat stability of P(IB‐aze‐St) was investigated by thermogravimetric analysis, and a 5% weight loss was found at 250 °C in air. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1515–1524, 2001     

Novel photocurable polyethers with methacrylate pendant groups

A method for preparation of novel fast photocurable polyethers is described. Thus, novel polyether, poly(3-methacryloxy propylene oxide) was obtained in low molecular weights (M_n: 1700 Da) by cationic ring opening polymerization of the epoxy group of glycidyl methacrylate (GMA) in presence of trimethylsilyl trifilate (TMSTF) as initiator. Copolymerization of the monomer with cyclohexene oxide (CHO) in the same reaction conditions yielded copolyethers with methacylate pendant groups. A series of copolymers with various GMA contents (10-100% mol/mol) were prepared using CHO as diluting comonomer. ¹H NMR spectra showed that oxirane function of GMA is somewhat less reactive than CHO. Having methacylate pendant groups the resulting waxy polymers underwent rapid photocrosslinking to give glassy hard materials upon UV irradiation at 350 nm, in the presence of benzoin as photoinitiator. Photocuring abilities of the copolymers were investigated by real time FT-IR using in dimethoxyethane solutions (14.7% w/w). The results showed that, 60% double bonds disappear within 150-300 s by irradiation of diluted copolymer solutions with Xenon lamp (150 W).     

Temperature‐dependent fluorescence from pyrenyl‐modified polyethylene films. A comparison of attachment methods and morphology changes by irradiation with eV‐range photons and bombardment with MeV‐range positive ions

1‐Pyrenyl groups were attached covalently to three polyethylene ( Py–PE ) films with different crystallinities by irradiating (eV‐range photons–UV‐photons) or by bombarding (MeV‐range ions–protons and alpha particles) pyrene‐doped PE films ( Py/PE ). Onset temperatures of relaxation processes (T_x) of the Py–PE were approximated from (1) Arrhenius‐type plots of the normalized integrated intensities of the films and (2) the temperature dependence of the full‐width half‐maximum (FWHM) films and the position of the 0–0 fluorescence band. DSC thermograms of the native and irradiated or bombarded films were also compared to independently assess the morphological changes. The onset temperatures T_x in lower crystallinity Py–PE films were more difficult to locate when prepared by bombardment with high doses than with low doses of photons or ions or by irradiation. The ease of locating the T_x in higher crystallinity Py–PE films was independent of dose, suggesting little change in the mobility in the vicinity of pyrenyl probes. Fluorescence from Py–PE bombarded with alpha particles indicated the presence of both singly‐ and doubly‐attached pyrenyl groups. The singly‐attached pyrenyl groups were less sensitive than the doubly attached to the T_x. Py–PE films were more sensitive luminescence reporters of T_γ segmental motions than were 9‐anthryl groups covalently attached to the same polymers. We also discuss possible reasons why the values of the activation energies for the relaxation processes, as calculated from the Arrhenius plots, were much smaller than those based on the dynamic mechanical methods. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2957–2970, 2004     

Mutual influence of LDPE and PP in their blends during crystallization

An indication for the mutual influence of LDPE and PP was the change of the morphology parameters of PE and PP at different ratios of the polymers in blends. That influence depends on the blend composition and is different for PE and PP. It is especially interesting in the blend PE75/PP25 where the influence between PE and PP shows dependence also on the sample geometry. Melting parameters, non-isothermal crystallization parameters - crystallization peak temperature T_c, crystallization begin temperature T_onset, half-width w_1/2 of the crystallization peak, degree of crystallinity α and crystallization rate coefficient CRC, as well as the isothermal kinetics parameters showed dependence on the blend composition. It was established that PE is more stable then PP concerning the mutual influence of both polymers on their crystallization. It was established that PE affects the crystal nucleation of PP and causes a decreasing of PP spherulite size.     

Synthesis and Properties of Phosphorus-Containing Aromatic Polyethers

The phosphorus-containing aromatic polyethers were prepared from bis(p-chlorophenyl)phenylphosphine oxide (BCPO) with the sodium salt of several bisphenols by high temperature solution polycondensation. The best result (yield 84%, n _sp /c = 0.15) was obtained from BCPO with bisphenol A (BPA) in dimethyl sulfoxide. However, the polymerization in the solvents such as N, N′-dimethyl-2-pyrrolidone, hexamethylphosphoramide, and N,N′-dimethylformamide, and the polymerization with the other bisphenols HO-C₆H₄-X-C₆H₄?OH, where X = CO, S0₂, CH₃P(O), C₆H₅P(O) in place of BPA gave gumlike polymers. The polymer prepared from BCPO and BPA did not decompose up to ca. 300°C under air or nitrogen atmosphere, but it decomposed slowly at 300–520°C, and decomposed rapidly at 520–540°C. The activation energy (δE) for the maximum rate of weight loss was 47.8 kcal/mole.     

Poly(aryl ethers) by nucleophilic aromatic substitution. I. Synthesis and properties

A series of new aromatic polyethers have been prepared by solution condensation polymerization. The synthesis involves the condensation of a dialkali metal salt of a dihydric phenol with an “activated” or negatively substituted aromatic dihalide in an anhydrous dipolar aprotic solvent at elevated temperatures. The reaction is rapid, free of side reactions, and yields polymers of excellent color. Bakelite polysulfone can be prepared in this manner by reaction of the disodium salt of bisphenol A with 4,4′-dichlorodiphenyl sulfone in dimethyl sulfoxide (DMSO). Only dipolar aprotic solvents are useful for conducting the polymerization. Of these, DMSO and Sulfolane (tetrahydrothiophene 1,1-dioxide) are the most effective. Water or other competing nucleophiles must be absent if high molecular weight is to be obtained. Besides providing the necessary solubility, this highly polar solvent is believed to be essential in providing the rapid polymerization rates observed. The rates are further found to depend on the basicity of the bisphenol salt and upon the electron-withdrawing power of the activating group in the dihalide. As is usual for this type of reaction, the difluorides are found to be more reactive than the corresponding dichlorides. Most of the polyethers are amorphous, rigid, tough thermoplastics with high second-order transitions (T_g). Thermal stability and electrical properties are noteworthy. These and other properties are described for polysulfone, and glass transitions are given for a selected list of the other polyethers.     

Synthesis of thermally-induced phase separating polymer with well-defined polymer structure by living cationic polymerization. I. Synthesis of poly(vinyl ether)s with oxyethylene units in the pendant and its phase separation behavior in aqueous solution

Living cationic polymerization of alkoxyethyl vinyl ether [CH₂?CHOCH₂CH₂OR; R: CH₃ (MOVE), C₂H₅ (EOVE)] and related vinyl ethers with oxyethylene units in the pendant was achieved by 1-(isobutoxy)ethyl acetate ( 1 )/Et_1.5AlCl_1.5 initiating system in the presence of an added base (ethyl acetate or THF) in toluene at 0°C. The polymers had a very narrow molecular weight distribution (M?_w/M?_n = 1.1–1.2) and the M?_n proportionally increased with the progress of the polymerization reaction. On the other hand, the polymerization by 1 /EtAlCl₂ initiating system in the presence of ethyl acetate, which produces living polymer of isobutyl vinyl ether, yielded the nonliving polymer. When an aqueous solution of the polymers thus obtained was heated, the phase separation phenomenon was clearly observed in each polymer at a definite critical temperature (T_ps). For example, T_ps was 70°C for poly(MOVE), and 20°C for poly(EOVE) (1 wt % aqueous solution, M?_n ～ 2 × 10⁴). The phase separation for each case was quite sensitive (ΔT_ps = 0.3–0.5°C) and reversible on heating and cooling. The T_ps or ΔT_ps was clearly dependent not only on the structure of polymer side chains (oxyethylene chain length and ω-alkyl group), but also on the molecular weight (M?_n = 5 × 10³-7 × 10⁴) and its distribution. © 1992 John Wiley & Sons, Inc.     

Ionic conductivity of complexes of novel multiarmed polymers with phosphazene core and LiClO4

Novel multiarmed polymers with ethylene oxide units, [( CH₂CH₂O)_n : 7, n = 3; 8, n= 7.2; 9, n = 11.8, and 12, n = 11.8] were prepared from the reaction of polyethylene glycol monomethyl ethers with acid chlorides of hexakis(3,5-dicarboxyphenoxy)-( 6 ) and hexakis(4-carboxyphenoxy)cyclotriphosphazenes ( 11 ) and conductivities of their Li⁺ salt complexes were investigated. The glass transition temperatures of the salt-free polymers are in the temperature range −59 to −54°C, indicative of a high degree of reorientational mobility of the arms. When LiClO₄ was added to the multiarmed polymers, the T_g values raised monotonically. The extent of T_g elevation was affected by the length of arms and the number of oxygen atoms around cyclotriphosphazene core and increased in the order 7 > 8 > 12 > 9 . The conductivities increased in the order 9 > 8 = 12 > 7 and the maximum conductivities of 4.0 × 10⁻⁵ S/cm at 30°C and 6.0 × 10⁻⁴ S/cm at 90°C have been achieved for the 9 -Li⁺ complex with Li⁺/O = 0.03. Interestingly, the conductivity of 9 -Li⁺ complexes at constant reduced temperatures increased in the whole concentrations of LiClO₄ examined (Li⁺/O = 0.01–0.2), although the degree of increase in conductivity above Li⁺/O = 0.06 became small. From the behaviors of T_g and the conductivity of multiarmed polymer–LiClO₄ complexes, it appears that the conductivity is governed by relative concentrations of inter- and intramolecular complexes in the polymer matrix. The influence of structural change of the comb-shaped to multiarmed polymers on the conductivity is described. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1839–1847, 1997     

Sulfone/ester polymers containing pendent ethynyl groups

Sulfone/ester polymers containing pendent ethynyl groups were prepared by multistep and direct routes. Hydroxy-terminated sulfone oligomers(M _n = 2650 and 8890 g/mol) were reacted with diacid chlorides to yield high-molecular-weight polymers. In the multistep route, a pendent bromo group on the polymer was converted to an ethynyl group. In the direct route, the hydroxy-terminated sulfone oligomers were reacted with a stoichiometric amount of 5-(4-ethynylphenoxy)isophthaloyl chloride to yield high polymers. The pendent ethynyl groups on the sulfone/ester polymers were reacted in the 200 to 300°C range to provide branching and crosslinking. The resultant polymers exhibited higher T_gs and better resistance to chloroform than comparable polymers void of ethynyl groups. Films of the cured polymers displayed good mechanical properties. The synthesis and characterization of the monomer, oligomers, and polymers are discussed.