Cationic polymerization by aromatic initiating systems. IV. Synthesis and characterization of α-ω-diphenylpolyisobutylene

The polymerization of isobutylene using ø₃Al coinitiator and the tertiary chlorides tert.-butyl chloride (t-BuCl) and 2,6-dichloro-2,6-dimethylheptane (Cl^t-R-Cl^t) initiators has been studied. Polymerization rates with the t-BuCl/ø₃Al and Cl^t-R-Cl^t/ø₃Al initiating systems were high in the ?20 to ?70°C range. Yields and molecular weights increased with decreasing temperature. As predicted by model experiments the extent of phenylation increases with decreasing temperatures. According to spectroscopic evidence the polyisobutylenes carry phenyl end groups.     

Block copolymer from α,ω-dihydroxyl polystyrene and polyethylene glycol

α,ω-Dihydroxyl polystyrene was synthesized by the addition of styrene oxide to polystyryl dianion initiated with sodium naphthalene. Diglyme was found to be an unsuitable solvent for the preparation of low molecular weight compounds. Block copolymerization of the α,ω-dihydroxyl polystyrenes (M?_n = 2250, 3140, and 6200) with poly(ethylene glycols) (M?_n = 404, 1960, and 5650) was pursued by introducing urethane linkages with 4,4′-diphenylmethane diisocyanate. The mechanical, thermal, and viscoelastic properties, solution viscosity, molecular weight distribution, and moisture absorption of the block copolymers obtained were examined. Incorporation of styrene blocks was found to disturb the crystallization and fusion of poly(ethylene glycol) blocks. Films cast from benzene solution were soft and elastic and absorbed up to 5.8% moisture.     

Study of the synthesis of poly(isobutylene-b-amide-11) by polycondensation α,ω-dianhydride oligoisobutylene with α,ω-diamino oligoamide-11. II. Synthesis of the block copolymers by reaction in solution

Several di-, tri- or multiblock poly(isobutylene-b-amide-11)s are prepared by reaction of α-mono or α,ω-dianhydride oligoisobutylenes with α-mono or α,ω-diamino oligoamides, in o-dichorobenzene at 140°C. They are characterized mainly by ¹H- and ¹³C-NMR spectroscopy and GPC, using the trifluoroacetylation technique. Their thermal differential chromatograms are reported and analyzed.     

α,ω-Dihydroxyalkan-α,α-diphosphonsäuren durch Desaminierung von ω-Aminoalkandiphosphonsäuren

α,ω-Dihydroxyalkane-α,α-diphosphonic Acids by Desamination of ω-Aminoalkanediphosphonic Acids The title compounds represent a new group of complexing diphosphonic acids which are synthesized by desamination of ω-amino-α-hydroxyalkane-α,α-diphosphonic acids. In case of α,ω-dihydroxypropane-α,α-diphosphonic acid ( 1 ) a phosphonylated phostone is formed by dehydration. In contrast, the ω-phenyl drivative of ( 1 ) yields in a smooth reaction under the same conditions 2-hydroxy-5-phenyl-3-phosphono-1.2-oxaphosphol-3-en-2-oxide ( 6 ).     

Preparation of α,ω-ditriazinylperfluoroalkane derivatives

The synthesis of 2-oxa and 2-thiaperfluoroglutaric acids and their corresponding ethyl esters, amides, nitriles, acid chlorides, and also 2-thiaperfluoroglutaric anhydride are described. These compounds were prepared as precursors to α,ω-ditriazinylperfluoroalkane derivatives containing a heteroatom in the perfluoroalkylene chain. The ditrazinylpropanes were prepared most satisfactorily from the diacid chlorides rather than the dinitriles.     

α,ω-diols from polymerization of ethylene

Polyethylene is prepared in silver perchlorate solution by initiation with dialkyl peroxydicarbonates at 0–40°C. Saponification of the polymer endgroups yields a product rich in α,ω-diols. Well-known reactions convert the hydroxyl groups to other functional groups. The diol may be condensed with phosgene so as to increase its molecular weight severalfold or crosslinked with silicon tetrachloride to form a network.     

Darstellung und Charakterisierung von α,ω-Dihydroperchloroligosilanen

Preparation and Characterization of α,ω-Dihydroperchloro Silanes Synthesis for the new compounds H(SiCl₂)_nH, n = 3?7 and HSi₄Cl₅ were described, starting from the perphenylated cyclosilanes. The new compounds were characterized and ¹H- and ²⁹Si-NMR spectra are discussed.     

Synthesis and phase‐separation behavior of α,ω‐difunctionalized diblock copolymers

A series of diblock copolymers of n‐pentyl methacrylate and methyl methacrylate (PPMA/PMMA BCP) with one or two terminal functional groups was prepared by sequential anionic polymerization of PMA and MMA using an allyl‐functionalized initiator and/or and end‐capping with allyl bromide. Allyl functional groups were successfully converted into OH groups by hydroboration. The morphology in bulk was examined by temperature‐dependent small‐angle X‐ray measurements (T‐SAXS) and transmission electron microscopy (TEM) showing that functional groups induced a weak change in d‐spacings L₀ as well as in the thermal expansion behavior. T‐SAXS proved that the lamellar morphologies were stable over multiple heating/cooling cycles without order‐disorder transition (ODT) until 300 °C. While non‐functionalized BCP formed parallel lamellae morphologies, additional OH‐termination at the PMMA block forced in very thin films (ratio between film thickness and lamellar d‐spacing below 1) the generation of perpendicular lamellae morphology through the whole film thickness, as shown by Grazing‐incidence small‐angle X‐ray scattering experiments (GISAXS) measurements. Functionalized BCP were successfully used in thin films as templates for silica nanoparticles in an in‐situ sol–gel process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Coupling of α,ω-dichloropoly(methylphenylsilane) and living poly(styryllithium). Study of the coupling reaction

Both di- and triblock copolymers consisting of polystyrene (PS) in conjunction with poly(methylphenylsilane) (PMPS) have been successfully prepared by coupling of α,ω-dichloro-PMPS with poly(styryllithium). The study of this reaction has shown a sudden limitation of the coupling yield, which however depends on the PS block length. Both the polymer concentration and the solvent have also an effect on the coupling reaction. Morphology of the PS-PMPS block copolymers has been observed by transmission electron microscopy. Very complex morphologies have been reported more likely as the result of the competition between the phase separation induced by PS and PMPS immiscibility and the tendency of PMPS to form ordered structures. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1939–1948, 1997     

α,ω-Glycols from copolymers of isobutylene and 2,5-dimethyl-2,4-hexadiene

Isobutylene has been copolymerized with 2,5-dimethyl-2,4-hexadiene using a boron trifluoride catalyst in petroleum ether solution. Ozonization of the products followed by reduction with lithium aluminum hydride has furnished polyisobutylene glycols in good yield.     

α,ω-Diisocyanatocarbodiimides, -Polycarbodiimides,and Their Derivatives

Research in the field of low-molecular weight, oligomeric and polymeric α,ω-diisocyanatocarbodiimides and -polycarbodiimides has been fruitful, not only in connection with these compounds themselves, but also—as so often happens in chemistry—with quite different problems. Novel synthetic methods, discoveries concerning the properties of low-molecular weight carbodiimides and phosphane imide derivatives, as well as results on the fragmentation reactions of four-membered heterocyclic compounds containing oxygen, phosphorus, and nitrogen, and a better understanding of the diisocyanate polyaddition process are among the many by-products of this research. The “high- and low-temperature formation” of polycarbodiimides and the homogeneous and heterogeneous catalysis of this process are described, and the fundamental importance of four-membered ring fragmentation mechanisms resulting in the formation of phosphane imide derivatives is outlined. Interesting building blocks for the diisocyanate polyaddition and polycondensation processes can be synthesized by many derivatization reactions of oligomeric and high-molecular weight polycarbodiimides and polyuretonimines. The in situ production of polycarbodiimides via matrix reactions in flexible polyurethane foams leads to a cellular arrangement of the material due to the pronounced symmetrical growth processes. Combination-foams with increased carbonation tendencies are formed in this way. Attention is drawn to several industrial applications of α,ω-diisocyanatopolycarbodiimides, of high-molecular weight cross-linked polyuretonimines, and of polycarbodiimide foams.     

Block copolymerization of tert‐butyl methacrylate with α,ω‐difunctionalized polystyrene macroiniferter and hydrolysis to amphiphilic block copolymer

The block copolymerization of tert‐butyl methacrylate (tBMA) with a difunctionalized polystyrene (PS) macroinitiator was investigated. The polymerizations were performed under UV light irradiation using PS bearing α‐ and ω‐functionalized end groups containing diethyldithiocarbamyl groups as a macroiniferter. Kinetic studies indicate the molecular weights of triblock copolymers increased linearly with the conversion. Block copolymers with different lengths of PtBMA segments were easily prepared by varying the ratio of tBMA and PS macroiniferter or by controlling the monomer conversion. The formations of block copolymers were characterized by gel permeation chromatographic, ¹H NMR, and DSC analyses. PtBMA segments of the triblock copolymer were subsequently hydrolyzed quantitatively to poly(methacrylic acid) segments using concentrated HCl as a catalyst in a refluxing solution of dioxane, and then an amphiphilic ABA triblock copolymer was produced. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1450–1455, 2001     

Structure and reactivity of α,β-unsaturated ethers. V. Cationic copolymerizations of ring-substituted phenyl vinyl ethers

Phenyl vinyl ether (M₁) has been copolymerized with its various ring-substituted derivatives (M₂) in toluene at ?78°C with stannic tetrachloride as catalyst. The substituents investigated include p-CH₃O, m-CH₃O, p-CH₃, m-CH₃, p-Cl, and m-Cl. The course of copolymerization was followed by gas chromatographic determinations of residual monomers, and the monomer reactivity ratios were evaluated by use of the integral form of the Mayo-Lewis copolymerization equation. Except for the unusual case of the m-CH₃O derivative, the observed values of log (1/r₁) were found to be linearly correlated with Hammett's σ constants, the reaction constant being ρ = ?1.76 with the correlation coefficient r = 0.990. Comparisons of these results with the existing data for the styrene copolymerizations have enlightened the behavior of the oxygen atom in transmitting the electronic effects of ring substituents onto the reaction center.     

Cationic polymerizations by aromatic initiating systems. III. Model reactions for initiation and termination using the t-BuCl/ϕ3Al and Clt-R-Clt/ϕ3Al systems

Preparatory for the synthesis of terminally functional polyisobutylenes carrying one or two phenyl end groups, model experiments have been carried out using novel tert-butyl chloride/triphenylaluminum and 2,6-dichloro-2,6-dimethylheptane/triphenylaluminum initiating systems. As anticipated, t-BuCl was phenylated by ø₃Al and the product is tert-butylbenzene. The reaction is extremely rapid and temperature has little effect on it in the 0 to ?60°C range. The interaction between the 2,6-dichloro-2,6-dimethylheptane and ø₃Al was found to be complicated by a proximity effect which leads to proton elimination in addition to phenylation. The formation of the desired diterminally phenylated product is not quanititative even at ?60°C.