Copolymers and terpolymers of sulfur dioxide with allyl monomers comprising groups absorbing ultraviolet irradiation

Alternating copolymers are obtained of sulfur dioxide with allyl phenyl ether, allyl p-nitrophenyl ether, N-allylbenzamide, N-allyl p-nitrobenzamide, allyl cinnamate and allyl o-benzoylbenzoate. Copolymerizations proceed in high yield at -78°C in the presence of tert-butyl hydroperoxide as initiator. However, copolymer yield is small for reactions initiated with 2,2′-azoisobutyronitrile at 50–60°C. Ultraviolet spectra of the copolymers obtained show the presence of intense absorption bands in the range of 220 to 305 nm. SO₂ terpolymers have been obtained with allyl ethers, allyl amides or allyl esters and 1-heptene, 2-methylpropene or methyl acrylate. The effect of the structure of the monomers on the reactivity in polymerizations involving SO₂ is discussed on the basis of the composition of the products.     

Lichtinitiierte polymer- und polymerisationsreaktionen, 26. Elektrophile ringöffnungsreaktionen zwischen glycidylethern und ketonen oder aldehyden initiiert durch photoinitiatorsysteme

By the irradiation of benzoin derivatives in the presence of arene diazonium salts or aryl iodonium salts cationic species are formed, which initiate ring-opening reactions of 2,3-epoxy-propyl (glycidyl) ethers in the presence of ketones or aldehydes. 1,3-Dioxolane formation dominates over homopolyaddition reactions of glycidyl ethers. This method forms dioxolane in satisfactory preparative yields. The quantum yields of disappearance of phenyl glycidyl ether in acetone (Φ_PGE) were measured in dependence of some system parameters. By the photolysis of benzil dimethyl ketal more catalytic species are produced as in the case of benzoin isopropyl ether or α-phenylbenzoin. The Φ_PGE values for diazonium salts are higher than for iodonium salts, with triphenylsulfonium salts the reaction failed. With the anions of iodonium salts the following sequence for Φ_PGE is observed: SbF₆^? > PF₆^? ? SbCl₆^? = BF₄^? = 0. Because the key step of the catalyst formation is an electron transfer reaction between radicals produced by the photolysis and the onium ions, the concentration of the salts influences Φ_PGE. Phenyl glycidyl ether reacts more rapidly than 2,2-bis(4-hydroxyphenyl)trimethylene diglycidyl ether and isobutyl glycidyl ether.     

Synthesis of ABC-triblock copolymers for light emitting diodes

In this paper we report on the synthesis and characterization of ABC-triblock copolymers poly(N-vinylcarbazole)-block-poly(4-(1-pyrenyl)butyl vinyl ether)-block-poly(2-[4-(2-phenyl-1,3,4-oxdiazolyl)phenyloxy]ethyl vinyl ether) 15 . The ABC-triblock copolymers were synthesized by sequential living cationic polymerization of N-vinylcarbazole 11 , 4-(1-pyrenyl)butyl vinyl ether 10 and 2-chloroethyl vinyl ether 3 . In a second step, the reactive pendant chloro groups of the poly(2-chloroethyl vinyl ether) segment of the block copolymers were substituted with 2-(4-hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole 6 to form fully functionalized ABC'-triblock copolymers. The molecular weight of the block copolymers varied from M _n = 4800 to 14000. The thermal behavior is discussed with respect to the block copolymer composition and compared with corresponding polymer blends. LED characteristics of a single layer device for one of the block copolymers are presented as an example.     

Thermal properties and crystallization behavior of poly(ether ether ketone ketone)/poly(ether biphenyl ether ketone ketone) copolymers

Thermal properties of poly(ether ether ketone ketone) (PEEKK)/poly(ether biphenyl ether ketone ketone) (PEDEKK) copolymers were investigated by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The glass transition temperature (T_g) increases from 154°C to 183°C as the content of PEDEKK units increases. The melting point (T_m) of the copolymers varied in the range between 314°C and 409°C and showed the behavior of eutectic type copolymer. From the investigation of the crystallization behavior of the copolymers, it was found that the cold-crystallization temperature (T_c′) of the amorphous copolymers assumes a maximum value for the copolymer with a mole fraction of the PEDEKK segment (n_B) of about 0.6, isothermally crystallized PEEKK and the PEEKK/PEDEKK copolymer exhibit double-melting behavior.     

New amphiphilic copolymers of N-phenylmaleimides and vinyl ethers: thermal properties,Langmuir and Langmuir-Blodgett films,gas permeation

Amphiphilic copolymers 1 a–1d were prepared by radical copolymerization of hydrophilic N-phenylmaleimide derivatives and lipophilic vinyl ethers in dichloromethane. Though the starting concentrations of the two monomers were always equimolar, none of the copolymers had a strictly alternating structure. Molecular weights were between 10⁴ and 9 · 10⁴. The copolymers prepared from ethyl 4-maleimidobenzoate ( 2a ) and isobutyl vinyl ether ( 3a ) (copolymer 1a ), and 2a and isooctyl vinyl ether ( 3b ) (copolymer 1b ) were thermally stable up to 300°C and showed glass transitions at about 150°C, while the copolymers prepared from 2a and octadecyl vinyl ether ( 3c ) (copolymer 1c ), and 4-maleimidobenzoic acid ( 2b ) and 3c (copolymer 1 d ) were considerably less stable. All copolymers formed stable, condensed monomolecular layers at the air-water interface, which could be transferred onto hydrophobic supports by the Langmuir-Blodgett (LB) technique. Up to the 20th dipping cycle, a Y-type deposition was found, while further dipping predominantly led to Z-type deposition. Nitrogen and oxygen permeabilities (p) were studied after depositing the LB films onto porous Celgard membranes. Permeability and selectivity were dependent on the nature of the alkyl substituent group of the polymer. Copolymer 1a with the isobutyl group showed higher permeabilities than copolymer 1c with the octadecyl group, but no selectivity. The copolymer with the small alkyl group showed no selectivity of oxygen over nitrogen (α = )P_O2/P_N2 while for the copolymer with the long alkyl chain the α-value was 1,3.     

Functional polymers and sequential copolymers by phase transfer catalysis, 1. Alternating block copolymers of unsaturated polyethers and aromatic poly(ether sulfone)s

Williamson etherification in the presence of phase transfer catalysts was successfully applied to the synthesis of alternating block copolymers and regular copolymers. Unsaturated polyethers( 5a and 5b ) containing chloroallylic (electrophilic) end groups (prepared from cis-or trans-1, 4-dichloro-2-butene and Bisphenol A) and aromatic poly(ether sulfone)s ( 3a ) containing terminal phenol (nucleophilic) groups were polycondensed in the presence of tetrabutylammonium hydrogen sulfate as phase transfer catalyst to give alternating block copolymers. The same telechelic polymers were chain-extended with dinucleophilic or dielectrophilic monomers under similar reaction conditions. Both the regular copolymers and the alternating block copolymers were characterized by gel pormeation chromatography and DSC.     

Syntheses and Properties of Novel Copolymers of Poly(1,4‐dioxane‐2‐one) and Aliphatic Polycarbonate Based on Ketal‐Protected Dihydroxyacetone

Novel random copolymers of 1,4‐dioxane‐2‐one (DON) and 2,2‐ethylenedioxy‐1,3‐propanediol carbonate (EOPDC) are synthesized in bulk at 120 °C using Sn(Oct)₂ as a catalyst. The effects of different molar feed ratios of EOPDC/DON on the yield and molecular weight of the copolymers are investigated. The copolymers are obtained with a yield of 55.4–98%. The number‐average molecular weight of the copolymer is 0.49–4.18 × 10⁴ g mol^?1 with a polydispersity of 1.52–1.68. The poly(DON‐co‐EOPDC)s obtained are characterized by FTIR, ¹H NMR, and ¹³C NMR spectroscopy, gel‐permeation chromatography (GPC), and DSC. The hydrolytic degradation of the copolymer in phosphate buffered saline (PBS) is also investigated. The results show that both the hydrophilicity and the degradation rate of the copolymers increase with increasing copolymer DON content.     

Metathesis degradation of polymers obtained by grignard-wurtz reaction of partially α-brominated 1,4-polybutadiene

1,4-Polybutadiene was partially brominated at the methylene groups with N-bromosuccinimide. Then, by means of Grignard-Wurtz reactions, the following substituents were introduced: isopropyl, butyl, pentyl, cyclohexyl, phenyl, 4-methylphenyl, 4-ethylphenyl, 3,4-dimethylphenyl, 4-isopropylphenyl, 4-fluorophenyl, 3-trifluorophenylmethyl, 4-chlorophenyl, benzyl, 2-methylbenzyl, and 4-methylbenzyl. The modified polymers (ca. 20% of the units substituted) were degraded to low molecular products with E-4-octene in the presence of the catalyst WCl₆/(CH₃)₄Sn. The degradation products were separated by gas chromatography and identified by mass spectrometry. Isomeric substituents, isomeric units, and isomeric segments in the polymers could be distinguished. — In Grignard-Wurtz reactions, transfer reactions with toluene as solvent and simultaneous reactions with two Grignard reagents (4-methylphenyl and 4-methylbenzyl compounds) were also investigated.     

Ternary ABC block copolymers based on one glassy and two crystallizable blocks: polystyrene-block-polyethylene-block-poly(ε-caprolactone)

The hydrogenation of polystyrene-block-polybutadiene-block-poly(ε-caprolactone) SBC triblock copolymers was performed in the presence of the Wilkinson catalyst RhCl(P(C₆H₅)₃)₃. Reaction conditions (hydrogen pressure, temperature and reaction time) were varied to ensure quantitative hydrogenation without detectable side reactions. Gel permeation chromatography showed no broadening of the molecular weight distribution during hydrogenation. The efficiency of the catalyst is markedly influenced by the molecular weight of the copolymer. Due to the presence of the polyethylene (PE) block, the resulting polymers exhibit a reduced solubility in comparison to the starting materials. Using differential scanning calorimetry (DSC), preliminary results about the crystallization and melting behavior of the PE-block were obtained. In the triblock copolymers, the PE-block showed a marked depression of the melting point and crystallinity when compared to pure hydrogenated polybutadiene of equivalent molecular weight and microstructure or to a comparable PE-block within a polyethylene-block-poly(ε-caprolactone) diblock copolymer. A fractionated crystallization process of the PCL-block was observed when the PCL component in the hydrogenated triblock copolymers was present as a minor phase.     

Synthesis and polymerization of epoxymethacrylates, 1. Catalysis and kinetics of the addition reaction of methacrylic acid and 2,2-bis[4-(2,3-epoxypropoxy)phenyl]propane

The kinetics of the addition reaction of methacrylic acid (1) and 2,2-bis[4-(2,3-epoxypropoxy)-phenyl]propane catalyzed by tertiary aliphatic amines, aromatic N-heterocycles and quaternary ammonium salts, respectively, was studied in bulk with equimolar amounts of functional groups from room temperature to 120°C. A reaction order of 1,5 with regard to the conversion of epoxy as well as carboxylic groups was observed. This can be explained assuming the formation of an ammonium alkoxide ion pair by the equilibrium reaction of an epoxy group with ammonium carboxylate and the irreversible consecutive reaction of the ion pair with (1) under formation of 2-hydroxyester groups and regeneration of ammonium carboxylate. The reaction rate constants increase linearly with the concentration of the catalyst and increase with increasing basicity of alkylpyridines. The advantage of the aromatic N-heterocyclic catalysts consists in their stability to peroxides which are ingredients of preparations together with the epoxy methacrylate Bis-GMA, e. g. in dental composites and adhesives.     

Copolymerization of ethylene and propene with soluble TiCl3 catalyst systems

For random copolymerization of ethylene and propene, the catalytic activity was studied of various catalyst systems consisting of TiCl₃ prepared by reduction of TiCl₄ with hydrogen. The extent of reduction of TiCl₄ markedly affects the activity of the catalyst. Furthermore, the combination of solvent and donor affects the activity, and 1,2-dichloroethane and dibutyl ether (DBE) was found to be the most favourable combination. Metal halides (MX_n) such as VCl₄ and VOCl₃ enhance the activity of the TiCl₃ catalyst. Concerning the co-catalyst, triisobutylaluminium results in the highest activity. As a whole, both the catalytic activity of these catalyst systems and the structure of the resulting copolymer are largely dependent on the solubility of the catalyst system. The copolymer obtained with a soluble TiCl₃ · DBE · Al(isobutyl)₃ system is highly isotactic in the PPP triad and has a lower content of inversion than a copolymer prepared with a conventional VOCl₃ catalyst system. Moreover, the copolymer obtained with the above TiCl₃ catalyst has superior physical properties, especially tensile properties, in comparison with the copolymer obtained with the conventional VOCl₃.     

Copolymerization of styrene and butadiene with Co(acac)3‐methylaluminoxane catalyst

The copolymerization of Styrene (St) and butadiene (Bd) with Co(acac)₃‐MAO catalyst was investigated. The copolymers consisting of St and Bd with highly cis‐1,4‐structure could be synthesized with Co‐(acac)₃‐MAO catalyst without formation of homopolymer, although the St contents in the copolymer were not high. The copolymer composition curve for copolymerization of St and Bd with the Co(acac)₃‐MAO is different from that obtained with the Ni(acac)₂‐MAO catalyst. The additive effects of triphenylphosphine (TPP) and trifluoroacetic acid (TFA) on the copolymerization of St and Bd with the Co(acac)₃‐MAO catalyst were also investigated. The copolymer yields increased by adding TPP to the Co‐(acac)₃‐MAO catalyst, although the St contents in the copolymer did not change. In the microstructure of the Bd units in the copolymers, 1,2‐contents increased remarkably. The copolymer yields and the microstructure of the copolymer did not change by addition of TFA.     

The heterogeneous modified-polypropene-supported Ziegler catalyst/MMAO system for producing ultrahigh molecular weight polyethene and poly(ethene-co-hex-1-ene) with a homogeneous comonomer distribution

A heterogeneous modified-polypropene-supported Ziegler catalyst (modified-PP-supported catalyst) combined with modified methylaluminoxane (MMAO) was successfully used for the production of ethene/hex-1-ene copolymers with a homogeneous distribution of hex-1-ene. The modified-PP-supported catalyst/MMAO also gave polyethene and ethene/hex-1-ene copolymers with ultrahigh molecular weight (M_w > 2×10⁶). The MMAO concentration and hex-1-ene content in the feed were found to affect the activity, comonomer content in the resulting copolymer, and melting temperature, while no influence on the molecular weight and comonomer distribution was detected.     

Copolymerisation von acetylen mit acetylenderivaten, 1. Copolymerisation von acetylen mit phenylacetylen

Copolymers were obtained from acetylene and phenylacetylene by coordinative polymerization with MoCl₅ as a catalyst in toluene as solvent. The copolymers were characterized by spectroscopic methods as well as by means of differential scanning calorimetry and gel permeation chromatography. The fraction of phenylvinylene units in the copolymers was determined by means of UV spectroscopy as well as the conjugation length of planar double bonds which increases with increasing fraction of vinylene units. The fraction of vinylene units in the copolymers was determined by IR spectroscopy. DSC measurements indicate the transformation temperature for isomerization, cyclization, aromatization and chain scission to decrease with increasing fraction of vinylene units. At high contents of vinylene units in the copolymers a trans-cisoide configuration is realised, while for pure polyphenylacetylene and copolymers with a low vinylene fraction the cis-transoide configuration is favoured. With increasing content of vinylene units the solubility of the copolymers decreases, while oxidizability and degradation reactions increase. These reactions are favoured at higher temperatures and upon light irradiation. The oligomeric fractions of the copolymers indicate the presence of biphenyl o,- m- and p-terphenyl, 1,1′:2′,1″:4′,1 ?- and 1,1′:3′,1″:5′,1 ?-quaterphenyl.     

Photo-oxydation des polyéther-bloc-polyamides, 2. Influence de la composition des polymères multiséquencés

Analytical and kinetical aspects of the photooxidation in the solid state of two polyether-block-polyamides 1c and 1d are described. The block copolymers studied contain different polyether sequences at different percentages. In copolymer 1d as well as in copolymers 1a and 1b , previously studied, the photooxidation concerns mainly the ether groups. High maximal concentrations of hydroperoxy groups, ? CH(OOH)? O? CH₂? , are observed (0,12 mol.kg^?1). These hydroperoxides are converted into hemi-acetals, ? CH(OH)? O? CH₂? , saturated esters and formate through photolysis or thermolysis above 60°C. The hemi-acetal groups are thermo-unstable too and decompose into alcohol and aldehyde groups. The photooxidation of copolymer 1c presents different features. At long wavelengths, low stationary concentration of hydroperoxy groups are observed (0,02 mol.kg^?1). Hydroperoxidation of the polyamide 6 sequences is revealed by the formation of imide groups. Hydroperoxidation of the poly(propylene glycol) sequences are surprisingly located on the ether methylene groups. Excitation of polyamide 6 sequences at short wavelength (254 nm) induces the formation of crotonized aldehyde groups.     

Fluorination of polymers containing COOH/COOR-groups with SF4/HF, 2

Carboxyl- and ester groups of low molecular-weight compounds are selectively and quantitatively converted into trifluoromethyl moieties by reaction with SF₄/HF as shown in a previous paper. This reaction is now applied to the polymers poly(acrylic acid), poly(acrylic esters) and poly[(acrylic acid)-co-(acrylic ester)]. Poly(acrylic acid) yields gelled products whereas poly(acrylic ester) and the copolymers yield highly fluorinated soluble polymers upon reaction with SF₄/HF. Under mild reaction conditions the carbonyl groups in acrylic acid/acrylic ester copolymers are selectively fluorinated. Unter vigorous reaction conditions, acid as well as ester moieties of the copolymers are completely fluorinated. Macroscopic gelation during fluorination is most probably associated with intermolecular ether formation. Molecular weights, NMR spectra and glass transition temperatures of the reaction products are given.     

A triple-bonds-containing poly(ether/ester): synthesis,characterization and cross-polymerization

A segmented poly(ether/ester) multiblock copolymer containing acetylene groups within the hard segment was synthesized starting from poly(ethylene glycol) with a number-average molecular weight M?_n = 1000, 2-butyne-1, 4-diol and terephthaloyl dichloride. Thermal and spectroscopic data suggest a blocky structure of the copolymer prepared. Nuclear magnetic resonance spectroscopy shows an average degree of polymerization of the hard segments of about 6. By heating in the presence or absence of a catalyst, the monoacetylene units in the hard segments are cross-polymerized below and above their melting temperature. The crosspolymerized material reveals a maximum gel fraction of 93,5 wt.-%, does not crystallize and shows reversible deformability in contrast to the starting polymer. In accordance with previous reports it is concluded that cross-polymerization is possible only in a polymer distinguished by some degree of chain ordering.     

New reactive polyethers: preparation and synthetic possibilities

Starting from 4-methoxycarbonylphenyl glycidyl ether and unfunctionalized phenyl glycidyl ether, samples of highly regio- and stereoregular linear homo- and copolymers were synthesized using the ionic coordinative initiator system aluminium isopropoxide/ZnCl₂. The polymers were first transformed into carboxylic acid derivatives and then into highly reactive carboxylic acid chlorides with high yields and conversions. The use of all these synthesized polymers was tested by transforming them into the corresponding 4-nitrobenzyl ester using different synthetic procedures. Finally, the scope of the methodology studied was tested by using it to synthesize a set of new polymers containing different complex groups such as: 18-crown-6, biphenyl-4-carbonitrile, anthraquinone, (1R)-nopol, (-)-inosine and 4-dodecylaniline, which are in general obtained with good yields and conversions.     

Synthesis of ethylene‐α‐olefin alternating copolymers with Et(1‐Ind)(9‐Flu)ZrCl2‐MAO catalyst system

Copolymerizations of ethylene and α‐olefins (4‐methyl‐1‐pentene, 1‐hexene, 1‐decene and 1‐hexadecene) were carried out with Et(1‐Ind)(9‐Flu)ZrCl₂‐MAO as the catalyst system. The degree of alternation in the resulting copolymers is higher than 92.1% for all the copolymers and close to 100% for ethylene‐1‐decene copolymer. Copolymerization behaviours focusing on the misinsertions during the polymerizations are investigated in detail from dyad and triad distributions estimated by ¹³C NMR analysis of copolymers. A reactivity ratio, r^B_E, was obtained for ethylene‐1‐hexene copolymers using a simplified two sites alternating mechanism and found to be 8.7, which is the same order of that reported in ethylene‐propene copolymerizations with Me₂C(3‐RCp)(Flu)ZrCl₂‐MAO as the catalyst system.     

Über den aufbau von block- und pfropfcopolymeren

After briefly introducing the basic possibilities for the formation of graft and blockcopolymers, the important methods of the radical-initiated block and graft copolymerization are discussed on the basis of the characteristic examples, which are available in the literature. Thereafter the discussion is carried out on the few a t that time known syntheses in the field of the anionic block copolymerization, which then finally loads to the own work with polyfunctional macromolecular anionic initiators. Thus the addition of dialkylaluminium hydrides to macromolecules with C?C double bonds in side chains or at chain ends, and treating the products with transitionmetal halides (e.g. TiCl₄), macromolecular ZIEGLER -NATTA -Catalysts are formed. These initiate graft and block copolymerization of ethylene and α-olefines, whereby the poly-α-olefine molecules, which are already grown, can have a stereoregular structure. Macromolecules containing RC?NM linkages are formed on addition of organometallic compounds of lithium (LiR) or magnesium (MgRhal) to the N≡C triple bond in styrene-acrylonitrile copolymers, and they initiate anionic graft copolymerization of acrylonitrile (AN), methylmethacrylate (MMA), 2-vinylpyridine (2-VP), and 4-vinylpyridine (4-VP). Reactions of macromolecules containing O?C, N≡C, or C?C linkages in side chains with sodium or naphthalene sodium give macromolecular radical anions (e.g., high-polymeric ketyls in the case of poly-p-vinylbenzophenone) or dianions, formed by electron-transfer from the metal to the multiple bond. Both the radical anions and the dianions initiate anionic graft copolymerization of AN, MMA, 2-VP, 4-VP, butadiene, and styrene, and in this way pure graft copolymers are formed, free from “backbone molecules” and from homopolymers of the grafted monomer. Pure graft copolymers are formed also on use of macromolecular organometallic initiators, such as those formed by metallation of poly-4-chlorostyrene or 4-chlorostyrene styrene copolymers with stoichiometric amounts of naphthalene sodium. Since the anionic end groups of the growing side chains remain “living” during these processes, second and third monomers can be added to afford graft copolymers whose side chains are block copolymers. If the growing chains are terminated, e.g., by chlorosilanes containing functional groups, then reactive end groups are introduced into the side chains. Finally, graft and, in particular, block copolymers can be obtained when “finished” macromolecules containing very reactive silicon side or end groups (e.g., H? Si-, Cl? Si-, HO? Si-, CH₂?CH? CH₂? Si-groups) are joined together by chemical reactions. These methods open a route to block copolymers having stereoregular blocks. Macromolecules containing suitable functional groups attached to silicon atoms also provide a bridge to anionic processes. For instance, macromolecules containing p-vinyl-phenylsilicon end groups surprisingly react readily with sodium to radical anions which effect block copolymerization of vinyl monomers.