Synthesis and Polymerization of (S)-4-Methyl-2-N,N-dimethylaminopentyl Methacrylate

(S)-4-Methyl-2-N,N-dimethylaminopentyl methacrylate (DMAPM) was synthesized from the reaction of N,N-dimethyl-L-leucinol with methacryl chloride, and its radical polymerization was investigated. It was found that DMAPM readily polymerized by α,α¹-azobisisobutyronitrile (AIBN) as an initiator to give poly-DMAPM. The copolymerization of DMAPM(M₁) with styrene(Mz) was also studied in various solvents with AIBN as an initiator at 60°C. From the result obtained in benzene, Q and e values of DMAPM were determined to be 0.64 and -0.04, respectively. Specific rotations of the copolymers of DMAPM with styrene were not proportional to the weight percent of the DMAPM unit incorporated, but the observed relation gave a downward curve. The copolymerizations DMAPM with α, β-disubstituted monomers such as maleic acid, maleimide, and N-phenylmaleimide were carried out in order to induce asymmetric center in the polymer chain. After hydrolysis of the copolymers obtained, the hydrolyzed polymers were found to be optically active, suggesting an induction of asymmetric center into the polymer chain.     

Vinyl Polymerization. 431. Vinyl Polymerizations Initiated by Block and Random Poly(Styrene-co-Sodium Methacrylate)

Abstract

The polymerization of some kinds of vinyl monomer was found to occur without an ordinary initiator in aqueous solutions of AB-type block or random copolymers of sodium methacrylate with styrene as a so-called “uncatalyzed polymerization.” Although the spin trapping technique showed that the initiation mechanism by the block copolymer was the same as that by the random copolymer, the initiating ability of the block copolymer was lower than that of the random copolymer. Such results are attributable to the difference in the incorporating ability of monomer into the micelles formed by the block copolymer and into the hydrophobic areas formed by the random copolymer.     

Nonclassical Urea Oligomers. VII. Binding Specificity of Carbanilido-ethylenimine Oligomer: Absorption Behavior in Suspension

Polyester elastomers were prepared by block copolymerization of dimethyl terephthalate (DMT), butanediol (BDO), and polytetramethylene glycol (PTMG). Polyester from DMT and butanediol forms a high-melting hard segment in block copolyester to prevent undue chain slippage when fibers are stretched. High elongation was provided by soft segment which consisted of condensation product from DMT and PTMG.

Experiments were carried out to determine the effect of composition variables on the properties of these elastomers, such as glass transition temperature, elongation at break, tenacity, and elastic recovery. The study on molecular characteristics of the elastic polyester showed that a leather-like region exists between glassy and rubbery regions. These elastomers were melt-spun to give elastic fibers which are competitive with commercially available Spandex-type fibers.     

Vinyl Polymerization. 436. Effect of Magnetic Field on Uncatalyzed Polymerization

The radical polymerization of vinyl monomers initiated with several kinds of hydrophilic macromolecule was carried out in a magnetic field. The magnetic field promoted the polymerization; the conversion of monomers and the molecular weight of the polymers obtained increased with increasing field strength in the range of 0–0.1 T. The dependence of the composition and tacticity of the mother polymer on the magnitude of the magnetic field was studied. Using graft or block copolymers, which consisted of hard and soft segments, the effect of a magnetic field was further investigated. The degree of hardness and tightness of the hydrophobic areas (reaction areas) formed by the mother polymer in the aqueous solution was found to affect the magnetic field effect on the uncatalyzed polymerization. The overall activation energy obtained in the magnetic field was almost equal to that obtained without a magnetic field.     

Design of Chitosan-5Fu Conjugate Exhibiting Antitumor Activity

In order to provide a macromolecular prodrug of 5-fluorouracil (5FU) reducing the side effects, having an affinity for tumor cells, and exhibiting strong antitumor activity, the covalent attachments of 5FUs to chitosan and chitosamino-oligosaccharide (COS) through hexamethylene spacer groups via urea, urea bonds were carried out. The effect of prolongation of life was tested in vivo against p388 lyrnphocytic leukemia in female CDF, mice by intra-peritoneal (i.p.) transplantation/i.p. injection and the growth-inhibitory effect on Meth-A fibrosarcoma or MH-134Y heputoma was evaluated in vivo in SPF-C3H/He scl male or Balb/c male mice by subcutaneous (s.c.) implantation/intravenous (i.v.) injection. The effects of the degree of polymerization of chitosan and     

Design,Synthesis, and Properties of Substituted Polyacetylenes

This article reviews recent topics on the polymerization of substituted acetylenes, focusing on the synthesis of poly(diphenylacetylenes) and the living polymerization of phenylacetylenes. Diphenylacetylene (DPA) polymerizes with TaCl_s-n-Bu₄Sn to give a polymer which is thermally very stable but insoluble in any solvents. DPAs with various groups (e.g.,p-Me₃Si,m-Me₃Ge, p-t-Bu,and_p-PhO) polymerize similarly. These polymers are soluble and their M¯_w's reach 1 × 10⁶ to 3 × 10⁶. Some of them are more gas-permeable than poly(dimethylsiloxane). Several acetylenes (e.g., ClC -n-C₆H₁₃ and HCUC-t-Bu) have been found to undergo living polymerization with MoOCl₄-n-Bu₄Sn-EtOH. Whereas phenylacetylene (PA) does not polymerize in a living fashion, ortho-substituents in PA more or less suppress termination and chain transfer. PAs with bulky ortho groups (e.g., CF₃ and Me₃Ge) especially undergo virtually ideal living polymerization.     

Oligosaccharide-Carrying Styrene-Type Macromers. Polymerization and Specific Interactions Between the Polymers and Liver Cells

Polystyrene derivatives with lactose, glucose, maltose, maltotriose, maltopentaose, and maltoheptaose on each benzene ring were prepared by the radical polymerization of a new class of macromers synthesized by coupling the corresponding oligosaccharide lactones with p-vinylbenzylamine. These polymers consisting of amphiphilic structural units were water-soluble, and organic solutes were bound to hydrophobic microenvironments of the polymers in water. α-D-Glucopyranose-carrying polymers were recognized and precipitated by concanavalin A. Cultivation of liver cells (hepatocytes) was attempted using culture dishes whose surface was coated with lactose-, glucose-, maltose-, and maltotriose-carrying polystyrenes. It has been found that a lactose-carrying polystyrene (PVLA) is a useful surface material for hepatocyte culture. 1) Highly specific adhesion of hepatocytes was attained for PVLA-coated dishes with or without serum supplement. 2) The cell adhesion was a threshold phenomenon with respect to the PVLA concentration on the dish. 3) The cell adhesion was effectively inhibited when hepatocytes were treated with PVLA molecules in the medium prior to culture. 4) The adhesion was not inhibited by albumin, an adhesion-inhibitory protein in serum. These findings suggest that pendent galactose residues of a PLVA molecule functioned as a strong recognition determinant for hepatocytes. We assume that multi-antennary, high-density galactose residues of PVLA are attributed to the specific adhesion of hepatocytes.     

Vinyl Polymerization. 269. Polymerization of Methyl Methacrylate Initiated by p,p'-Dimethoxydiphenyldiazomethane

Using p,p'-dimethoxydiphenyldiazomethane (DMDM) as initiator, the polymerization of methyl methacrylate (MMA) in benzene or in bulk was carried out. The initial rate of polymerization, R_p, was found to be expressed by the following equation:

R_p = k[DMDM]^0.53 [MMA]^0.84

The polymerization was confirmed to proceed by a radical mechanism. The over-all activation energy for the polymerization in benzene was calculated as 19.3 kcal/mole. The rate of thermal decomposition of DMDM was also measured in benzene and the rate equation was obtained as follows:

k_d (sec^?1) = 1.0 × 10¹⁵ exp (^?29.1 kcal/RT) (for 50-80°C)

Explanations of these observations are discussed in connection with those of the preceding papers.     

Vinyl Polymerization. 439. Vinyl Polymerization Initiated by Poly(Ethylene Glycol] Diglycolic Acid or its Sodium Salt

Abstract

The polymerization of some kinds of vinyl monomer was found to occur in aqueous solutions of poly(ethylene glycol) diglycolic acid (PEG Acid) or sodium poly(ethylene glycol) diglycolate (PEG Acid Na) through radical mechanisms without any further initiator, as a so-called “uncatalyzed polymerization.” Although the initiating radical species for PEG Acid was determined to be the same as that for PEG Acid Na by means of the spin-trapping technique, the initiating ability of PEG Acid was higher than that of PEG Acid Na. These results are assumed to be attributable to the difference in the initiation mechanisms of the two systems and in the incorporating abilities of monomer into the hydrophobic areas formed by PEG Acid and PEG Acid Na.     

Influences of aging on thermal decomposition mechanism of high performance oxidizer ammonium dinitramide

Ammonium dinitramide (ADN) is one of the several promising new solid propellant oxidizers. ADN is of interest because its oxygen balance and energy content are high, and it also halogen-free. One of the most important characteristics of a propellant oxidizer, however, is stability and ADN is known to degrade to ammonium nitrate (AN) during storage, which will affect its performance. This study focused on the effects of aging on the thermal decomposition mechanism of ADN. The thermal behaviors of ADN and ADN/AN mixtures were studied, as were the gases evolved during their decomposition, using differential scanning calorimetry (DSC), thermogravimetry–differential thermal analysis-infrared spectrometry (TG–DTA-IR), and thermogravimetry–differential thermal analysis-mass spectrometry (TG–DTA-MS). The results of these analyses demonstrated that the decomposition of ADN occurs via a series of distinct stages in the condensed phase. The gases evolved from ADN decomposition were N₂O, NO₂, N₂, and H₂O. In contrast, ADN mixed with AN (to simulate aging) did not exhibit the same initial reaction. We conclude that aging inhibits early stage, low temperature decomposition reactions of ADN. Two possible reasons were proposed, these being either a decrease in the acidity of the material due to the presence of AN, or inhibition of the acidic dissociation of dinitramic acid by NO ₃ ^? .