Radiation Degradation of Poly(olefin Sulfone)s: A Volatile Product Study

The predominant degradation reaction in the γ-irradiation of nine poly(olefin sulfone)s was found to be C-S bond scission with elimination of SO₂ and olefin. The extent of depolymerization, measured by the yields of the two comonomers, increased over five irradiation temperatures from 0 to 150° C and could be correlated with the ceiling temperature. Thus G (total volatile products) increased from 10 to 10,000 over this temperature range. Minor radiolysis products included the alkanes corresponding to (1) loss of the side chain group and (2) scavenging of the side chain radical by monomer olefin. There was a deficiency of olefin relative to SO₂, except at high temperatures, and isomerization of the product olefin in some cases. These observations are attributed to reactions of radiation-induced polymeric cations.     

Propagation/depropagation equilibrium and structural factors in the radiation degradation of poly(olefin sulfone)s

The principal volatile products observed after γ irradiation of nine different poly(olefin sulfone)s in the solid state were the two comonomers, i.e., the respective olefin and sulfur dioxide. An exponential increase in yield, G(volatile products), with increasing irradiation temperature, T_irr, was observed for each copolymer through the ceiling temperature, T_c, for the corresponding propagation/depropagation equilibrium. Thus the G value increased by ca. 3 orders of magnitude from T_irr = 0.7 T_c to T_irr = 1.3 T_c for all of the poly(olefin sulfone)s. Depropagation sensitivity was considered to be best measured by G(SO₂) since radiation induced, cationic homopolymerization of the product olefin occurred to a variable extent. Five of the poly(olefin sulfone)s had similar rates of depropagation at their respective T_c's but the polysulfones of 1-hexene, cyclohexene and 2-butene showed anomalously high depropagation rates. This may be related to greater steric hinderance to segmental chain mobility in the polysulfones of the 1,2 disubstituted olefins. Poly(1-hexene sulfone) appears to be anomalous, as in other respects.     

氧化偶联聚合的方法合成新型电活性聚醚砜及其结构表征

通过氧化偶联聚合的方法我们制备了一种新型电活性聚芳醚砜,这种聚合物主链上含有苯基封端的苯胺四聚体齐聚物单元。我们通红外、核磁和XRD对其结构进行了表征。在1.0M的硫酸水溶液介质中我们对其电活性进行了研究,聚合物展现出两对氧化还原峰。此外,我们使用TGA测试手段对其热稳定性也做了研究。在室温质子酸掺杂的条件下聚合物的导电率为1.37 × 10-7 S·cm-1。     

Thermal degradation of poly(olefin sulphone)s. Part I—The effect of olefin structure on the yields of volatile products

The rates and mechanisms of the thermal degradation of nine alternating poly(olefin sulphone)s with different olefin structures have been investigated at 150°C and 200°C by a novel technique which is particularly suitable for studying the initial steps of the degradation. Rapid degradation was initiated at the CS bond with depolymerisation to sulphur dioxide and olefin. The rate of thermal degradation showed a moderate correlation with the ceiling temperature for monomer-polymer equilibrium and also with the number of β-hydrogen atoms, but neither parameter provided an adequate measure of the sensitivity of all the poly(olefin sulphone)s to thermal degradation. Substantial isomerisation was observed in the formation of olefin from poly(3-methyl-1-butene sulphone).     

Kinetics of thermal degradation of poly(aryl ether)s containing phthalazinone and life estimation

New special engineering thermoplastics, poly(phthalazinone ether sulfone) (PPES) and poly(phthalazinone ether sulfone ketone) (PPESK), containing phthalazinone are synthesized through step-polymerization. The kinetics of thermal degradation of PPES and PPESK (1/1) in nitrogen is investigated at several heating rates by thermogravimetry (TG). It is concluded that, based on using Satava’s theory, the thermal degradation mechanism of PPESK (1/1) is nucleation and growth, the order of reaction of the degradation process is one (n = 1). In contrast, the thermal degradation mechanism of PPES is a phase boundary controlled reaction and the order of the reaction is two (n = 2). The kinetic parameters, including reaction energy and frequency factor of thermal degradation reaction for PPES and PPESK (1/1) are analyzed using isoconversional Friedman, Kissinger–Akahira–Sunose (K–A–S) and Ozawa method. In addition, the study focus on the influence of heating rate and ratio of ketone/sulfone on thermal stability and the life estimation are described.     

Photoinduced unzipping depolymerization of poly(olefin sulfone)s possessing photobase generator and base amplifier

The photoinduced depolymerization of poly(olefin sulfone)s was investigated. Poly(olefin sulfone)s possessing base‐amplifying groups were synthesized. A photobase‐generating compound was mixed with poly(olefin sulfone)s and irradiated with 254 nm UV light. The decomposition ratio was significantly enhanced in poly(olefin sulfone)s that possessed base‐amplifying groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 602–613, 2009     

Synthesis of aromatic polymers via palladium-catalyzed cross-coupling reactions with magnesium,zinc, and tin reagents: A comparison

Difunctional magnesium, zinc, and tin reagents M?C₆H₄?O?C₆H₄?M (M = MgBr, ZnCl, SnBu₃) in the presence of palladium or nickel catalysts undergo cross-coupling polymerizations with aromatic, heteroaromatic, benzylic, and allylic dihalides to give oligomeric and polymeric materials. Tin reagents lead to products of higher molecular weight than Mg and Zn reagents. The reaction is sensitive to the solvent and enhanced by magnesium halides. Increased reaction temperatures lead only to moderate increases in the degree of polymerization and are limited by catalyst decomposition above 200°C. The new poly(ether ketone) and poly(ether sulfone) type polymers prepared show high thermal stability. In contrast to conventional poly(ether sulfones)s, the biphenyl-based sulfone polymers reported here are crystalline. © 1992 John Wiley & Sons, Inc.     

聚(苯乙烯砜)的热降解研究

<正> 由苯乙烯与二氧化硫共聚合生成的聚(苯乙烯砜)是一种良好的耐干法刻蚀的正性电子束阻蚀剂。近年来,国内外对其聚合条件以及作为阻蚀剂的物化性能等有较多的研究。但关于其热性能的研究报道甚少。Bowden等研究聚(苯乙烯砜)热降解时,发现其热分解温度在290℃以上。而国际商用机械公司(IBM)的报告则认为在135℃左     

Comparative non-isothermal kinetic analysis of thermal degradation of poly(vinyl chloride) prepared by living and conventional free radical polymerization methods

Non-isothermal kinetics of the thermal degradation of poly(vinyl chloride) (PVC) prepared by a living radical polymerization (LRP) method was performed and compared with the results obtained from PVC prepared by the conventional free-radical process (FRP). Both differential and integral isoconversional methods were applied for determining the apparent activation energy of the dehydrochlorination stage. This study made clear noticeable differences in the thermal degradation of the PVC samples under analysis. The newly synthesized LRP-PVC material has a better thermal stability and presents substantial differences in the macroscopic kinetics of the dehydrochlorination process compared with conventional FRP-PVC. These differences were assessed in quantitative terms on the basis of the kinetic triplet [E_a,A,f(α)].     

Synthesis, characterization and properties of heat-resistant and soluble poly(aryl ether)s containing s-triazine units in the main chain

Soluble and heat-resistant s-triazine-containing poly(aryl ether)s have been prepared for their potent utilities as high-temperature membranes and composite matrix materials. They have been synthesized by the nucleophilic displacement polymerization of 2,4-bis(4-fluorophenyl)-6-phenyl-1,3,5-triazine (BFPT) with each of resorcinol (RS), 4,4′-dihydroxydiphenyl sulfone (DS), and bisphenol-like 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (HP). The presence of meta-ether linkages, sulfone groups or phthalazinone moieties in the polymer chain results in an improvement in the solubility of s-triazine-containing poly(aryl ether)s in common organic solvents (e.g., N,N′-dimethylacetamide, N-methyl-2-pyrrolidinone). The new polymers are amorphous and exhibit excellent thermal stability. The apparent activation energy values (E_a) as determined by using Kissinger method are respectively 268.1, 245.9 and 215.1 kJ/mol under N₂ flow in dynamic heating conditions, for the first degradation stage of RS-PE, DS-PE and HP-PE, which are in well agreement with those values (272.6, 249.9 and 239.1 kJ/mol) determined by using Flynn-Wall-Ozawa method. The thermal stability classification among the polymers is made on the basis of the E_a values, and it follows the decreasing order: RS-PE > DS-PE > HP-PE. The properties of these polymers have been also compared with those of corresponding poly(aryl ether)s.     

Sulfur-containing polymers. Synthesis and properties of novel poly(arylene thioether)s based on 2,2-bis(4-mercaptophenyl)propane

Novel poly(arylene thioether)s were synthesised using the one pot polymerisation method from the bis(N,N-dimethyl-S-carbamate) of 2,2-bis(4-mercaptophenyl)propane and activated difluoro aromatic compounds. Each of the polymers, obtained in good yields and with fairly high molecular weights, were characterised by IR, GPC and NMR analyses. In particular, the NMR characterisation was performed using ¹H NMR, ¹³C NMR, DEPT, 2D COSY and 2D HSQC experiments. To study the effect on the thermal properties of replacing the ethereal oxygen atoms with sulfur atoms, we have synthesised the counterparts, the poly(arylene ether)s, with similar molecular weights. We observed that the substitution of the ethereal oxygen atoms with sulfur atoms results in a slightly lower thermal stability for the poly(thioether ketone)s, both under nitrogen and in air, and does not modify the T_g values. For the poly(thioether sulfone), on the other hand, the thermal stability is equal to that of the poly(ether sulfone), while the T_g is 10 °C lower. Furthermore, each sample is completely amorphous, with the exception of one of the poly(thioether ketone)s (sample 1b), which shows the capacity to crystallise, even if with a very slow crystallisation kinetics.     

Photoinduced depolymerization in poly(olefin sulfone) films comprised of volatile monomers doped with a photobase generator

Photoinduced depolymerization of poly(olefin sulfone)s mixed with a photobase generating compound was investigated. Irradiation of 254 nm UV light to films comprising of a mixture of a photobase generating compound and poly(olefin sulfone)s with volatile monomers caused photoinduced depolymerization and the irradiated part of the film vaporized. The effect of the poly(olefin sulfone) structure on the photoinduced depolymerization process was investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Facile synthesis of linear–hyperbranched polyphosphoesters via one‐pot tandem ROMP and ADMET polymerization and their transformation to architecturally defined nanoparticles

A convenient one‐pot synthesis of linear–hyperbranched polyphosphoesters (l–HBPPEs) was accomplished by a tandem ring‐opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polymerization procedure. A linear monotelechelic poly(norbornene) with a terminal acrylate and many pendent thiol groups is first prepared through adding an internal cis‐olefin terminating agent to the reaction mixture immediately after the completion of the living ROMP, and then utilized as a macromolecular chain stopper in subsequent ADMET polymerization of a phosphoester functional AB₂ monomer, yielding l–HBPPEs as the reaction time prolonged. These l–HBPPEs bearing lots of pendent thiol groups in linear poly(norbornene) and peripheral acrylate groups in HBPPE could be self‐crosslinked in ultradilute solution through thiol‐Michael addition click reaction between acrylate and thiol to give single‐molecule nanoparticles with comparatively uniform size. This facile approach can be extended toward the fabrication of novel nanomaterials with sophisticated structures and tunable multifunctionalities. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 964–972     

以二氟烷基磺酸修饰的聚降冰片烯为基础的聚合物电解质薄膜的制备

合成了一种新型的二氟烷基磺酰氟单体2-（双环[2.2.1]庚-5-烯-2）-1,1-二氟-2-甲氧基丙基-1-磺酰氟.首先利用二氟甲基2-吡啶基砜和2-乙酰基-5-降冰片烯发生亲核加成反应,在低温下用三氟甲磺酸甲酯保护加成产物中的羟基,之后在KOH/MeOH的条件下脱去吡啶基,得到的二氟亚磺酸盐和Slectfluor试剂反应制得想要的二氟烷基磺酰氟单体.这种新型的二氟烷基磺酰氟单体和不同比例的降冰片烯单体在Grubbs第二代催化剂存在条件下进行开环烯烃复分解聚合（ROMP）,所得的聚合物在碱性条件下水解,再用稀盐酸处理最终制得新型的含有二氟烷基磺酸的聚合物电解质膜.这些新型的聚合物电解质膜具有中等的室温质子电导（12～49mS/cm）.     

Polymerization of butadiene sulfone

Polymerization of butadiene sulfone (BdSO₂) by various catalysts was studied. Azobisisobutyronitrile (AIBN), butyllithium, tri-n-butylborn (n-Bu)₃B, boron trifluoride etherate, Ziegler catalyst, and γ-radiation were used as catalysts. Butadiene sulfone did not polymerize with these catalysts at low temperatures (below 60°C.), but polymers were obtained at high temperature with AIBN or (n-Bu)₃B. The polymerization of BdSO₂ initiated by AIBN in benzene at 80–140°C. was studied in detail. The obtained polymers were white, rubberlike materials and insoluble in organic solvents. The polymer composition was independent of monomer and initiator concentrations and reaction time. The sulfur content in polymer decreased with increasing polymerization temperature. The polymers prepared at 80 and 140°C. have the compositions (C₄H₆)_1.55- (SO₂) and (C₄H₆)_3.14(SO₂), respectively, and have double bonds. These polymers were not alternating copolymers of butadiene with sulfur dioxide. The polymerization mechanism was discussed from polymerization rate, polymer composition, and decomposition rate of BdSO₂. From these results, the polymerization was thought to be “decomposition polymerization,” i.e., butadiene and sulfur dioxide, formed by the thermal decomposition of BdSO₂, copolymerized.     

Norbornene polymerization using multinuclear nickel catalysts based on a polypropyleneimine dendrimer scaffold

Four multinuclear nickel complexes derived from generation 1 (G1) and generation 2 (G2) dendrimeric salicylaldimine ligands based poly(propyleneimine) dendrimer scaffolds of the type, DAB-(NH₂)_n (n = 4 or 8, DAB = diaminobutane) were evaluated as catalysts precursors in the polymerization of norbornene, using methylaluminoxane as co-catalyst. All four catalyst evaluated were found to be active for norbornene polymerization giving polymers with moderate to high molecular weights and low polydispersity indices. The polymerization results indicate that there is some sort of dendritic effect, in that the catalyst activity appears to be influenced by the dendrimer generation.     

The influence of cross-linking agents on ring-opening metathesis polymerized thermosets

The addition of suitable cross-linking agents with norbornene-based monomers has significant effects on the thermal properties of the resulting polymers formed by olefin metathesis. Ethylidene norbornene (ENB) and endo-dicyclopentadiene (endo-DCPD) were mixed separately with various loadings of three different cross-linking agents and then polymerized with the addition of Grubbs’ catalyst. The polymerization kinetics and resulting glass transition temperature (T _g) of the systems were evaluated by differential scanning calorimetry (DSC). The addition of the first cross-linking agent, norbornadiene (CL-1), to both endo-DCPD and ENB resulted in decreasing glass transition temperatures with increasing concentrations. In contrast, the addition of the other two cross-linking agents (CL-2 and CL-3), which were both custom synthesized bifunctional norbornyl systems, to both endo-DCPD and ENB resulted in a monotonic increases in T _g with cross-linker concentration. By tailoring the loading of these custom cross-linking agents, the properties of these polymer systems can be controlled for various applications, including self-healing composites.     

Synthesis and characterization of novel heat resistant poly(amide imide)s

A series of new poly(amide imide)s was prepared from new diacid containing sulfone, ether, amide and imide groups with various aromatic diamines. The diacid was synthesized via four steps, starting from reaction of 4-aminophenol with 4-nitrobenzoyl chloride in the presence of propylene oxide afforded N-(4-hydroxy phenyl)-4-nitrobenzamide. In the second step, reduction of nitro group resulted in preparation of 4-amino-N-(4-hydroxy phenyl) benzamide. In the next step for the preparation of diamine, the reaction of 4-amino-N-(4-hydroxy phenyl) benzamide with bis-(4-chlorophenyl) sulfone in the presence of K₂CO₃ was achieved. The prepared sulfone ether amide diamine was reacted with two moles of trimellitic anhydride to synthesize related sulfone ether amide imide diacid. The precursors and final monomer were characterized by FT-IR, H-NMR and elemental analysis. Direct polycondensation reaction of the sulfone ether amide imide diacid with different diamines in the presence of triphenyl phosphite afforded five different poly (sulfone ether amide imide amide)s. The obtained polymers were fully characterized and their physical properties including thermal behavior, thermal stability, solubility, and inherent viscosity were studied.     

Fluorinated poly(ether sulfone)s

New fluorinated poly(ether sulfone)s were prepared from bisphenols and α,ωbis(4-fluorophenylsulfonyl)perfluoroalkanes. The fluorinated sulfone monomers were synthesized by reaction of 4-fluorobenzenethiol salts with perfluoroalkylene diiodides, followed by oxidation. Sodium carbonate mediated polymerization gave high molecular weight polymers in excellent yield. The polymers are generally soluble in chlorinated hydrocarbons and some dipolar solvents, are amorphous with T_g's in the range of 120–160°C and are stable to 400°C. They form clear, colorless films by solution casting. Cast films have dielectric constants and dissipation factors somewhat below those of typical poly(ether sulfone)s, and show good permeability and selectivity for O₂/N₂ gas separations.     

Synthesis and characterizations of novel phosphorous-nitrogen containing poly(ether sulfone)s

The synthesis of novel phosphorus-nitrogen synergism aromatic poly(ether sulfone)s was carried out successfully by using phosphorus-containing and nitrogen-containing biphenol-like monomers, 1,1′-bis(4-hydroxyphenyl)-metheylene-bispheny-1-oxophosphine oxide (DOPO-PhOH) and 1,2-dihydro-4-(4-hydroxyphenyl)phthalazin-1(2H)-one (DHPZ), in the usual synthesis procedure. Polymers with sufficient molecular weights could be obtained. The structure of the phosphorus-nitrogen containing poly(ether sulfone)s was characterized by means of Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance spectroscopy (¹H NMR, ³¹P NMR). The influence of monomer ratio on their thermal stability was also investigated by adjusting the proportion of DOPO-PhOH/DHPZ (mol/mol) from 80/20 to 20/80. The molecular weight and glass-transition temperatures (T_g′s) of the polymers increased with increasing content of the DHPZ monomer. The high thermal stabilities were depended on the different proportion of diol type incorporated.