Novel polysulphonates and poly(sulphonate-co-carbonate) polymers for nuclear track detection

Preparation of homopolymer from diethylene glycol bis(allyl sulphonate) (DEAS) and its several copolymers with allyl diglycol carbonate (ADC) and their preliminary evaluation as nuclear track detector is described. The monomer is synthesized by reacting diethylene glycol with allyl sulphonyl chloride in presence of pyridine as a base. Spectral characteristics of the monomer are also given for the first time. The designed polymers were successfully tested for detection of ²³⁹Pu alpha particles and ²⁵²Cf fission fragment tracks after etching with 6 N NaOH at 70 °C. Some of the polymers prepared showed even better sensitivity than (SR-86)(20) track detectors for track detection properties. The polymers are also compared with commercial CR-39 track detectors for its track detection properties.     

Polymeric Nitrofuran Derivatives. I. Radical-Initiated Homo- and Copolymerization of 5-Nitrofurfuryl Methacrylate

The radical homopolymerization of 5-nitrofurfuryl methacrylate (NFMA) and the copolymerization of NFMA with methyl methacrylate and various vinyl monomers, respectively, have been studied in dimethylformamide at 65°C. NFMA and poly(NFMA) have been characterized by ¹H-NMR, IR, and UV spectroscopy. The influence of polymerization conditions on monomer conversion and on the molecular weight of the polymers obtained has been investigated. The thermal behavior of the polymers obtained has been studied by TGA and DSC analysis.     

Synthesis and photopolymerization of 1-propenyl glycidyl ether

The ambifunctional monomer, 1-propenyl glycidyl ether, was prepared from allyl glycidyl ether, by a ruthenium-catalyzed isomerization reaction in high yield. 1-Propenyl glycidyl ether undergoes facile photoinduced cationic polymerization to yield a crosslinked polymer. The structure of this polymer was studied using ¹H- and, ¹³C-NMR spectroscopies and employing well-characterized related polymers as models. The model polymers were prepared by the cationic polymerization of allyl glycidyl ether with BF₃OEt₂ followed by isomerization of the pendant allyl groups by a ruthenium catalyst. Subsequently, the resulting polyether-bearing pendant 1-propenyl ether groups was subjected to a diaryliodonium salt-photoinitiated polymerization. A comparison of the spectra of the polymers indicated the presence of cyclic acetal units in the polymer backbone. © 1994 John Wiley & Sons, Inc.     

New hyperbranched carbosiloxane–carbosilane polymers with aromatic units in the backbone

New hyperbranched polymers based on a carbosiloxane–carbosilane skeleton with aromatic units in the backbone have been prepared via one-pot hydrosilylation reaction using HSi(Me)₂–O–CH₂–C₆H₄–OSiMe–(CH₂)₄(C₃H₅)₂ as a novel AB₂ monomer. These polymers are easy to prepare, have narrow polydispersity values and present allyl groups on the surface which can be used as synthetic platforms for the introduction of different terminal groups like amine groups through hydrosilylation reactions, opening the door to functionalized polymers. The polymerization process was monitored using real-time ¹H NMR spectroscopy and the resulting hyperbranched polymers were characterized using ¹H NMR, ¹³C NMR, ²⁹Si NMR and SEC/MALLS. The degree of branching in these polymers was determined by quantitative ²⁹Si NMR spectroscopy and found to be very close to the theoretical value of 0.50 for AB₂ systems. The hydrolytic degradation of these polymers in protic solvents has been studied by ²⁹Si NMR.     

Soluble high polymers from allyl methacrylate

Allyl methacrylate has been polymerized by free-radical methods and found to yield a soluble polymer in carbon tetrachloride, dioxane, and diallyl ether solutions. The overall rate equation in diallyl ether is R_p = k[ln]^0.7[M]^1.6. It is suggested that propagation and cyclization reactions proceed only via addition to the methacrylyl groups of the monomer. Some degradative chain transfer occurs with the allyl groups, and it is considered that the solvents may ensure the production of soluble polymers by reactions in which allyl–radical side chains are terminated without crosslinking.     

Thianthrene as an activating group for the synthesis of poly(aryl ether thianthrene)s by nucleophilic aromatic substitution

A method for the preparation of poly(aryl ether thianthrene)s has been developed in which the aryl ether linkage is generated in the polymer‐forming reaction. The thianthrene heterocycle is sufficiently electron‐withdrawing to allow fluoro displacement with phenoxides by nucleophilic aromatic substitution. The monomer for this reaction, 2,7‐difluorothianthrene, can be synthesized in a moderate yield by a simple reaction sequence. Semiempirical calculations at the PM3 level suggest that 2,7‐difluorothianthrene is sufficiently activated, whereas NMR spectroscopy (¹H and ¹³C) indicates that the monomer is only slightly activated or (¹⁹F) not sufficiently activated for nucleophilic aromatic substitution. Model reactions with p‐cresol have demonstrated that the fluorine atoms on 2,7‐difluorothianthrene are readily displaced by phenoxides in high yields, and the process has been deemed suitable for polymer‐forming reactions. High‐molecular‐weight polymers have been produced from bisphenol A, bisphenol AF, and 4,4′‐biphenol. The polymers have been characterized with gel permeation chromatography, NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. The glass‐transition temperatures for the polymers of different compositions and molecular weights range from 138 to 181 °C, and all the polymers have shown high thermooxidative stability, with 5% weight loss values in an air environment approaching 500 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6353–6363, 2004     

Synthesis and properties of semiconducting aromatic polyquinonediimines

A new class of poly-conjugated polymers has been obtained by condensation of anthraquinones with aromatic diamines in polyphosphoric acid. The polymers are black, intractable powders. Toward obtaining tractable materials, the effect of monomer structure on polymer tractability has been studied. Copolymerizations were also carried out to “soften” these materials. Electrical conductivities in the semiconducting range, 10^?4- 10^?8 (ohm cm)^?1 were observed. Doping with iodine showed small increases.     

Insertion Homo‐ and Copolymerization of Diallyl Ether

The previously unresolved issue of polymerization of allyl monomers CH₂?CHCH₂X is overcome by a palladium‐catalyzed insertion polymerization of diallyl ether as a monomer. An enhanced 2,1‐insertion of diallyl ether as compared to mono‐allyl ether retards the formation of an unreactive five‐membered cyclic O‐chelate (after 1,2‐insertion) that otherwise hinders further polymerization, and also enhances incorporation in ethylene polymers (20.4 mol %). Cyclic ether repeat units are formed selectively (96 %–99 %) by an intramolecular insertion of the second allyl moiety of the monomer. These features even enable a homopolymerization to yield polymers (poly‐diallyl ether) with degrees of polymerization of DP_n≈44.     

Reversible addition–fragmentation chain transfer mediated radical polymerization of asymmetrical divinyl monomers targeting hyperbranched vinyl polymers

Reversible addition–fragmentation chain transfer (RAFT) mediated radical polymerizations of allyl methacrylate and undecenyl methacrylate, compounds containing two types of vinyl groups with different reactivities, were investigated to provide hyperbranched polymers. The RAFT agent benzyl dithiobenzoate was demonstrated to be an appropriate chain‐transfer agent to inhibit crosslinking and obtain polymers with moderate‐to‐high conversions. The polymerization of allyl methacrylate led to a polymer without branches but with five‐ or six‐membered rings. However, poly(undecenyl methacrylate) showed an indication of branching rather than intramolecular cycles. The hyperbranched structure of poly(undecenyl methacrylate) was confirmed by a combination of ¹H, ¹³C, ¹H–¹H correlation spectroscopy, and distortionless enhancement by polarization transfer 135 NMR spectra. The branching topology of the polymers was controlled by the variation of the reaction temperature, chain‐transfer‐agent concentration, and monomer conversion. The significantly lower inherent viscosities of the resulting polymers, compared with those of linear analogues, demonstrated their compact structure. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 26–40, 2007     

Synthesis and characterization of polymers containing linear sugar moieties as side groups

The synthesis of a water-soluble monomer, namely 4-vinylphenyl-d-gluco(d-manno)hexitol (4) derived from d-gluconolactone, is here presented. The homopolymerization of the vinylsugar has been conducted in both aqueous and organic media using free-radical initiators. High-molar-mass water-soluble polymers are obtained. The copolymerization behavior of the vinylphenyl sugar monomer with a hydrophilic monomer such as acrylamide, as well as with a hydrophobic monomer such as styrene, has been investigated. Statistical- and block-type copolymers have thus been prepared. The structures of the polymers were confirmed by NMR and their thermal properties examined by DSC.     

Modeling the free radical polymerization of acrylates

Acrylates have gained importance because of their ease of conversion to high‐molecular‐weight polymers and their broad industrial use. Methyl methacrylate (MMA) is a well‐known monomer for free radical polymerization, but its α‐methyl substituent restricts the chemical modification of the monomer and therefore the properties of the resulting polymer. The presence of a heteroatom in the methyl group is known to increase the polymerizability of MMA. Methyl α‐hydroxymethylacrylate (MHMA), methyl α‐methoxymethylacrylate (MC₁MA), methyl α‐acetoxymethylacrylate (MAcMA) show even better conversions to high‐molecular‐weight polymers than MMA. In contrast, the polymerization rate is known to decrease as the methyl group is replaced by ethyl in ethyl α‐hydroxymethylacrylate (EHMA) and t‐butyl in t‐butyl α‐hydroxymethylacrylate (TBHMA). In this study, quantum mechanical tools (B3LYP/6‐31G*) have been used in order to understand the mechanistic behavior of the free radical polymerization reactions of acrylates. The polymerization rates of MMA, MHMA, MC₁MA, MAcMA, EHMA, TBHMA, MC₁AN (α‐methoxymethyl acrylonitrile), and MC₁AA (α‐methoxymethyl acrylic acid) have been evaluated and rationalized. Simple monomers such as allyl alcohol (AA) and allyl chloride (AC) have also been modeled for comparative purposes. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

通过活性自由基聚合制备结构精致的大分子单体

合成了一种新型单体引发转移终止剂,2-N,N-二乙基二硫代氨基甲酰氧基乙酸烯丙酯(ADCA)。在紫外光照射下,引发剂量的ADCA能分别引甲基丙烯酸甲酯(MMA)和苯乙烯(St)聚合,聚合过程具有活性聚合的特征,即所得聚合物的数均分子量随着单体转化率的增加而线性增加,经1^HNMR分析证明,所得聚合物为一大分子单体,具有α-烯丙氧基羰甲基和ω-N,N-二乙基二硫代氨基甲酰氧基(DC)基团的精致结构。大分子单体的分子量可通过控制聚合过程中的单体转化率和所用引发剂浓度来调节。运用ESR技术证明了聚合反应机理。     

Preparation of functional polymers by living anionic polymerization: Polymerization of allyl methacrylate

The anionic polymerization of allyl methacrylate was carried out in tetrahydrofuran, both in the presence and in the absence of LiCl, with a variety of initiators, at various temperatures. It was found that (1,1-diphenylhexyl)lithium and the living oligomers of methyl methacrylate and tert-butyl methacrylate are suitable initiators for the anionic polymerization of this monomer. The temperature should be below −30°C, even in the presence of LiCl, for the living polymerization to occur. When the polymerization proceeded at −60°C, in the presence of LiCl, with (1,1-diphenylhexyl)-lithium as initiator, the number-average molecular weight of the polymer was directly proportional to the monomer conversion and monodisperse poly(allyl methacrylate)s with high molecular weights were obtained. ¹H-NMR and FT-IR indicated that the α CC double bond of the monomer was selectively polymerized and that the allyl group remained unreacted. The prepared poly(allyl methacrylate) is a functional polymer since it contains a reactive CC double bond on each repeating unit. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2901–2906, 1997     

Synthesis,characterization, and thermally activated curing of oligosiloxanes containing benzoxazine moieties in the main chain

Oligosiloxanes containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diallyl functional monomer is synthesized through the Mannich and ring closing reaction of 4,4′‐isopropylidenediphenol (bisphenol A), formaldehyde and allylamine. Hydrosilylation reaction of the resulting diallylic monomer (B‐ala) with 1,1,3,3‐tetramethyldisiloxane (TMDS) in the presence of Pt catalyst yields the corresponding poly(B‐ala‐tetramethyl disiloxane)s (PBTMDS) with the molecular weights in the range of 1800–4100 Da. The structures of the precursor diallyl monomer and the resulting polymers are confirmed by FT‐IR and ¹H NMR analysis. Curing behavior of both the monomer and polymers has also been studied by Differential Scanning Calorimetry (DSC). Flexible free standing transparent films of the oligosiloxanes are obtained by solvent casting from dichloromethane solution on Teflon plates. The films preserve shape and, to some extent, toughness after thermal curing between 100 and 180 °C. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 804–811, 2009     

Microporous structure of highly permeable additive silicon-containing polytricyclononenes

The porosity of a number of additive silicon-containing polytricyclononenes from the class of highly permeable polymers has been systematically studied for the first time by the method of low-temperature nitrogen adsorption/desorption. It has been shown that these polymers have a large specific surface area (390?790 m²/g) and are microporous. Dominant pore size ranges from 7 to 10 Å depending on the number of Me₃Si groups in a monomer unit and their relative position.     

Controlled/living free‐radical copolymerization of 4‐(azidocarbonyl) phenyl methacrylate with methyl acrylate under 60Co γ‐ray irradiation

A new vinyl acyl azide monomer, 4‐(azidocarbonyl) phenyl methacrylate, has been synthesized and characterized by NMR and FTIR spectroscopy. The thermal stability of the new monomer has been investigated with FTIR and thermal gravimetry/differential thermal analysis (TG/DTA), and the monomer has been demonstrated to be stable below 50 °C in the solid state. The copolymerizations of the new monomer with methyl acrylate have been carried out at room temperature under ⁶⁰Co γ‐ray irradiation in the presence of benzyl 1H‐imidazole‐1‐carbodithioate. The results show that the polymerizations bear all the characteristics of controlled/living free‐radical polymerizations, such as the molecular weight increasing linearly with the monomer conversion, the molecular weight distribution being narrow (<1.20), and a linear relationship existing between ln([M]₀/[M]) and the polymerization time. The data from ¹H NMR and FTIR confirm that no change in the acyl azide groups has occurred in the polymerization process and that acyl azide copolymers have been obtained. The thermal stability of the polymers has also been investigated with TG/DTA and FTIR. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2609–2616, 2007     

Neue modifizierte Polycarbosilane

Poly(allymethylsilyene-co-benzylidene) is obtained by treatment of allymethyldichlorosilane with α,α-dibromotoluene and magnesium as reducing agent. The polymer reacts with triflic acid under substitution of the allyl group to give the triflate derivative. The conversion of this compound with element hydrogen compounds and triethylamine or with lithium salts leads to numerous new functionally substituted polycarbosilanes. The modified polymers have been characterised by NMR spectroscope (²⁹ Si, ¹³C,¹H).     

Pursuit of reinitiation efficiency of resonance‐stabilized monomeric allyl radical generated via “degradative monomer chain transfer” in allyl polymerization

For a deeper understanding of allyl polymerization mechanism, the reinitiation efficiency of resonance‐stabilized monomeric allyl radical was pursued because in allyl polymerization it is commonly conceived that the monomeric allyl radical generated via the allylic hydrogen abstraction of growing polymer radical from monomer, i.e., “degradative monomer chain transfer,” has much less tendency to initiate a new polymer chain and, therefore, this monomer chain transfer is essentially a termination reaction. Based on the renewed allyl polymerization mechanism in our preceding article, the monomer chain transfer constant in the polymerization of allyl benzoate was estimated to be 2.7 × 10^?2 at 80 °C under the polymerization condition, where the coupling termination reaction of growing polymer radical with allyl radical was negligible and, concurrently, the reinitiation reaction of allyl radical was enhanced significantly. The reinitiation efficiencies of monomeric allyl radical were pursued by the dead‐end polymerizations of allyl benzoate at 80, 105, and 130 °C using a small amount of initiators; they increased remarkably with raised temperature. Thus, the enhanced reinitiation reactivity of allyl radical at an elevated temperature could bias the well‐known degradative monomer chain transfer characteristic of allyl polymerization toward the chain transfer in common vinyl polymerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Polymerization of epoxides with dialkylaluminum acetylacetonate catalyst systems

Catalyst systems for the polymerization of epichlorohydrin, propylene oxide, and allyl glycidyl ether have been prepared from pure, separately synthesized dialkylaluminum acetylacetonates (R₂Alacac). Adding small amounts of water to R₂Alacac gives a catalyst system with enhanced activity. An even more active catalyst system for yielding high molecular weight, epichlorohydrin-containing polymers is obtained when another organometallic compound is added to the R₂Alacac-0.5 water components. The R₂Alacac-0.5 water-R₂Zn system has been studied in detail. Variation in the molar proportion of water and structural changes in the chelate structure of the R₂Alacac component have been examined. Results indicate that the bis-chelate structure, acac(R)-Al-O-Al(R)acac, plays a major role in catalyst formation. A bimetallic catalyst species containing aluminum and zinc atoms is proposed, with zinc functioning primarily in monomer coordianation and with aluminum involved primarily in polymer chain growth.     

Synthesis of Novel Glycidol Copolymers with Pendant Alkene and Hydroxyl Groups

A series of linear poly glycidol copolymers, tethering with both alkene and hydroxyl groups, were prepared by a combination of anionic ring-opening polymerization （ROP） using specific reactions of ethoxy ethyl glycidyl ether （EEGE） and allyl glycidyl ether （AGE） firstly, and subsequently removal of the protection group of glycidol in EEGE to achieve the linear copolymer pendant with both hydroxyl groups and double bonds. The EEGE/AGE monomer reactivity ratio is measured to be 3.30/1.13. The chemical compositions of the as-synthesized polymers were characterized by tH NMR and GPC, and the glass transition temperatures （Tg） of as-synthesized polymers were determined by DSC. The final copolymers have abundant double bonds and hydroxyl as side groups. Furthermore, the ratio of the double bonds to hydroxyl groups can be controlled by the ratio of the starting materials in a wide range.