Showing papers in "Polymer Bulletin in 1978"
TL;DR: Cationic polymerisations of n-butylvinylether, tetrahydrofuran and a typical bis-epoxide are readily induced in the presence of AgPF6 by thermal and photochemically active sources of free radicals.
Abstract: Cationic polymerisations of n-butylvinylether, tetrahydrofuran and a typical bis-epoxide are readily induced in the presence of AgPF6 by thermal and photochemically active sources of free radicals.
57 citations
TL;DR: In this paper, the use of conditions favoring retro Diels-Alder reaction of crosslinks (treatment with maleic anhydride at elevated temperature) was proved that crosslinks are largely reversible.
Abstract: PVC undergoes rapid crosslinking during thermal degradation. Diels-Alder addition of conjugated polyenes was proposed as a possible crosslinking mechanism by earlier authors. By the use of conditions favoring retro Diels-Alder reaction of crosslinks (treatment with maleic anhydride at elevated temperature) it was proved that crosslinks are largely reversible. Evidently Diels-Alder addition of the conjugated polyenes plays an important role in crosslinking during thermal degradation of PVC.
36 citations
TL;DR: In this article, the Tg of amorphous linear polyethylene has been studied using torsion braid analysis and 4 transitions are observed: at 150, 190, 260, and 370°K.
Abstract: The Tg of amorphous linear polyethylene has been studied using torsion braid analysis. 4 transitions are observed: at 150°K, 190°K, 260°K and 370°K. Our results indicate that linear polyethylene has 2 glass transitions, a Tg(L) at 190°K, corresponding to the truly amorphous polymer and a Tg(U) at 260°K corresponding to the amorphous regions constrained by crystalline regions.
28 citations
TL;DR: In this article, wood meal with aqueous alkali in the presence of anthraquinone at 80°C was treated with a conversion of reducing hexose end groups in the polysaccharides to mannonic and gluconic acid end groups.
Abstract: Treatment of wood meal with aqueous alkali in the presence of anthraquinone at 80°C leads to a conversion of reducing hexose end groups in the polysaccharides to mannonic and gluconic acid end groups. Xylose end groups are oxidized to xylonic and lyxonic acid groups. This leads to a stabilization of the polysaccharides against endwise alkaline degradation.
23 citations
TL;DR: In this article, a polymer and an oligomer were found to have about one butyl group incorporated through the attack of C4H9Li on the carbonyl group.
Abstract: Methyl methacrylate-d8 was polymerized by C4H9Li in toluene at −78°C and the resultant polymer and oligomer were studied for butyl group by 1H NMR spectroscopy according to the precision coaxial tubing method (HATADA 1977a). A polymer and an oligomer molecule was found to have about one butyl group incorporated through the attack of C4H9Li on the carbonyl group as well as one terminal butyl group. The total amount of the C4H9Li residue introduced in both the polymer and oligomer molecules was measured to be 0.45mmol and almost corresponded to the amount of the C4H9Li used (0.50mmol).
16 citations
TL;DR: As a new type of the nucleic acid analogs, poly-L-lysine derivatives containing adenine, thymine and uracil derivatives were prepared by using the activated ester method and the content of adenines unit in the polymer was less than that of the thymine analog.
Abstract: As a new type of the nucleic acid analogs, poly-L-lysine derivatives containing adenine, thymine and uracil were prepared. By using the activated ester method, carboxyethyl derivatives of the nucleic acid bases were grafted onto poly-L-lysine. The thymine and uracil derivatives were completely substituted to poly-L-lysine. The content of adenine unit in the polymer, however, was less than that of the thymine analog.
15 citations
TL;DR: The poly(BOL) membrane prepared by casting polymerization exhibited an excellent fractional solute-rejection behavior in the aqueous solution, having a comparatively sharp boundary region at the molecular weight range of about 200 to 1400, together with an extremely high water permeability as discussed by the authors.
Abstract: The poly(BOL) membrane prepared by “casting polymerization” exhibited an excellent fractional solute-rejection behavior in the aqueous solution, having a comparatively sharp boundary region at the molecular weight range of about 200 to 1400, together with an extremely high water permeability. These conspicuous behaviors, as well as a great capacity for water absorption, may result from some delicate arrangement of polar hydrophilic and nonpolar hydrophobic microdomains probably formed along and between the polymer chains.
15 citations
TL;DR: In this article, a water-insoluble poly (β-diketone) chelating resin has been prepared by the controlled oxidation of poly(vinyl alcohol) with chromic acid.
Abstract: A water-insoluble poly (β-diketone) chelating resin has been prepared by the controlled oxidation of poly(vinyl alcohol) with chromic acid. The polymer forms stable complexes with divalent and trivalent cations, such as Co+2, Cu+2, Mn+2, Ni+2, Fe+3, Au+3, and UO2+2, and removes them completely from dilute aqueous solution. The ions may be recovered quantitatively from the resin complex by elution with dilute aqueous acid and the resin is reusable
15 citations
TL;DR: In this article, asparagine and isoasparagine were converted into polyaspartic acids by refluxing the corresponding aqueous solutions at neutral pH in the presence of a salt.
Abstract: Both asparagine and isoasparagine were converted into polyaspartic acids by refluxing the corresponding aqueous solutions at neutral pH in the presence of a salt. The properties of the resulting polyaspartic acids were studied. The dissociation behavior of the carboxyl groups in the polypeptides were studied by the potentiometric titration. The analysis of the titrational data was performed by a modified Speakman's method. The analysis show that both polyaspartic acids prepared from asparagine and isoasparagine have α- and β-aspartyl residues and the ratio of α- and β-aspartyl residues is 75 ∶ 25∼85 ∶ 15. A possible mechanism for the formation of α- and β-aspartyl residues in the polymer was discussed.
14 citations
TL;DR: In this article, the 13C NMR spectra of H-H PS and PVCH were used to compare the microstructure of different chemical ways to identify the stereosequences.
Abstract: The 13C NMR spectra of H-H PS and H-H PVCH show the influence of the long range order on the chemical shift of several carbons. There is some hope to improve the resolution by the choice of appropriate solvents. The attribution of the lines to specific stereosequences would require the preparation and separation of optically pure dimers and trimers. It is, however, already possible to compare the microstructure of H-H polymers prepared by different chemical ways.
14 citations
TL;DR: In this article, the phase equilibrium of poly(p-phenyleneterephthalamide) was quantitatively investigated by using a typical rod-like polymer in a mixed solvent system and the experimental results may afford a basis on the formation of liquid crystal of the polymer.
Abstract: The phase equilibrium was quantitatively investigated by using a typical rodlike polymer, poly(p-phenyleneterephthalamide), in mixed solvent system. The experimental results may afford a basis on the formation of liquid crystal of the polymer.
TL;DR: Spontaneous alternating copolymerizations of 2-phenyl-1,3,2-dioxaphospholane (MN) with p- and with o-formylbenzoic acids (ME) were examined in this article.
Abstract: Spontaneous alternating copolymerizations of 2-phenyl-1,3,2-dioxaphospholane (MN) with p- and with o-formylbenzoic acids (ME) were examined. The copolymerizations took place without catalysts affording the copolymer 3 via zwitterion 6. The copolymerizations involve the oxidation of the phosphorus monomer and the reduction of formylbenzoic acid. The scheme of the copolymerizations was presented. The yields of copolymers were quite different between these two copolymerizations. With ortho acid, the copolymer yield was low due to producing phthalide 4.
TL;DR: Polarized Raman spectra of doubly oriented samples of atactic poly(vinyl alcohol) have been measured in this article, and the great usefulness of such polarized spectra has been clarified for the vibrational analysis.
Abstract: Polarized Raman spectra of doubly oriented samples of atactic poly(vinyl alcohol) have been measured. The great usefulness of such polarized spectra has been clarified for the vibrational analysis. The normal coordinate treatments of syndiotactic and isotactic poly(vinyl alcohol) chain models gave good agreement between the observed and calculated frequencies.
TL;DR: In this paper, a copolymer of methyl methacrylate-d8 (M1) with a small amount of trityl (M2) was radically prepared in tetrahydrofuran.
Abstract: Copolymer of methyl methacrylate-d8(M1) with a small amount of trityl methacrylate(M2) was radically prepared in tetrahydrofuran and converted into the copolymer of methyl methacrylate-d8 with a small amount of undeuterated methyl methacrylate by the selective hydrolysis of the trityl group and subsequent methylation with diazomethane. From the 1H NMR spectrum of the derived copolymer the assigned coisotactic parameters σ12 and σ21 were determined to be 0.14 and 0.61, respectively. This may be the first example of the unequivocal determination of assigned configurational parameters in cross propagation for copolymerization.
TL;DR: In this paper, the nucleic acid base substituted l-lysine derivatives were prepared from α,N-Cbz-l-lysines and the p-nitrophenyl esters of the carboxyethyl derivatives of the nucleIC acid bases.
Abstract: Poly-l-lysines containing nucleic acid bases, that is, adenine, thymine, uracil and theophylline were synthesized. The nucleic acid base substituted l-lysine derivatives were prepared from α,N-Cbz-l-lysine and the p-nitrophenyl esters of the carboxyethyl derivatives of the nucleic acid bases. The polymers were obtained from these l-lysine derivatives by the NCA method.
TL;DR: In this article, the morphological influence of water-soluble polymers on the aqueous bilayer aggregate (vesicle and/or lamella) of didodecyldimethylammonium bromide was investigated by electron microscopy.
Abstract: The morphological influence of water-soluble polymers on the aqueous bilayer aggregate (vesicle and/or lamella) of didodecyldimethylammonium bromide was investigated by electron microscopy. Positively charged polymers and uncharged polymers either destroyed the aggregate or was ineffective. On the other hand, the negatively-charged copolymer of acrylamide and acrylate separated the bilayer and produced smaller vesicles.
TL;DR: In this paper, a monomer of nucleophilic reactivity (M N) reacts with another monomer having electrophilic reactivities (M E ) to generate a key + intermediate of zwitterion MN-M E.
Abstract: We have d e v e l o p e d a s e r i e s o f new c o p o l y m e r i z a t i o n s which occur without added catalyst and proceed through zwitterion intermediates (SAEGUSA et al, 1975a, b; 1976a; 1977a). In these copolymerization, a monomer of nucleophilic reactivity (M N) reacts with another monomer having electrophilic reactivity (M E ) to _ generate a key + intermediate of zwitterion MN-M E . On the basis of this concept we found new polymer synthesis reactions to form polyphosphinate 7 from 4 and 2a (SAEGUSA et al, 1976b) and polyphosphate 8 from 1 and 5 ~SAEGUSA et al, 1977b). In both cases, 1 and 4 acted as nucleophilic monomer (M N) and 2 and 5
TL;DR: In this article, a brief kinetic study is reported of the polymerisation of ethylene catalysed by four aluminium-titanium chloro-organic complexes, three of which are new.
Abstract: A brief kinetic study is reported of the polymerisation of ethylene catalysed by four aluminium-titanium chloro-organic complexes, three of which are new. These systems proved efficient both in terms of polymerisation rate and of the linearity of the high polymers obtained. A comparison is made with previous work in this field.
TL;DR: In this paper, the photochemistry of benzoin derivatives in a polymer medium leads to the suggestion that oxygen play an important part in the first processes which occur under U.V. irradiation.
Abstract: Investigation of the photochemistry of benzoin derivatives in a polymer medium leads to the suggestion that oxygen play an important part in the first processes which occur under U.V. irradiation. This is of interest for the understanding of the photocrosslinking process.
TL;DR: The membrane of poly(3-O-vinylbenzyl gluconate-co-acrylonitrile) is found to be effective for permeative separation of metal ions and the high selectivity and high permeation rate are discussed in connection with the chelate formation and the hydrophilicity of ion channel.
Abstract: The adsorption and permeation of metal ion mixtures were examined for the membrane of poly(3-O-vinylbenzyl gluconate-co-acrylonitrile). The membrane is found to be effective for permeative separation of metal ions. For the Cu/Cd combination, especially, Cu ion was selectively adsorbed and permeated in a neutral aqueous solution. The high selectivity and the high permeation rate are discussed in connection with the chelate formation and the hydrophilicity of ion channel.
TL;DR: In this article, the effect of solvents and initiators was discussed in correlation with the mechanism, and it was shown that at low temperature polymer formation accompanied by dioxane type dimer through back-biting reaction was predominant.
Abstract: Dioxolane type dimer and trioxane type trimer were the principal product in the cationic polymerization of isobutylene oxide at room temperature. At low temperature polymer formation accompanied by dioxane type dimer through back-biting reaction was predominant. At room temperature, hydride transfer occurs easily to form isomerized oligomers. The effect of solvents and initiators was discussed in correlation with the mechanism.
TL;DR: In this article, concentrated solutions of poly (γ -benzyl L-glutamate) (PBLG) were investigated using small angle light scattering (SALS) in terms of theories previously developed for SALS from crystalline polymers.
Abstract: Concentrated solutions (>20 wt%) of poly (γ -benzyl L-glutamate) (PBLG) were investigated using small angle light scattering (SALS). The gels and cholesteric liquid crystals formed in PBLG concentrated solutions, were analyzed in terms of theories previously developed for SALS from crystalline polymers. It was found that there are two types of the fibrillar aggregation of α-helices in gels and furthermore, two types of the orientation correlation of α-helices in cholesteric liquid crystals.
TL;DR: In this paper, a new reversible photochromic copolymer of maleic anhydride with styrene containing azo side groups was presented, which reacts to irradiation by a reversible trans-cis photoisomerization of light-sensitive azo groups.
Abstract: A new reversible photochromic copolymer of maleic anhydride with styrene containing azo side groups was prepared. The system reacts to irradiation by a reversible trans-cis photoisomerization of light-sensitive azo groups. Irradiation also causes a change in the refractive index, so that the polymer may be employed in recording optical information in the form of phase hologram. The resolution of the material is higher than 2000 lines/mm. In spite of the large variability of organic compounds, according to available information only two groups of compounds have been utilized in the reversible recording of volume phase holograms. These are dimers of aromatic polycyclic hydrocarbons (Tomlinson et al. 1972) and stilbene derivatives (Anonym 1974). In this paper we describe a new reversible material for recording volume phase holograms (Matějka et al. 1978).
TL;DR: In this paper, the lifetime of the propagating species and initiation rate constants (ki) were evaluated for the cationic polymerization of p-methoxystyrene initiated by I2, CH3SO3H, BF3O(C2H5)2, and SnCl4.
Abstract: Lifetime of the propagating species and initiation rate constants (ki) were evaluated for the cationic polymerization of p-methoxystyrene initiated by I2, CH3SO3H, BF3O(C2H5)2, and SnCl4. The lifetime was found to be fairly long, ranging from 0.2 to several seconds in 1,2-dichloroethane at 30°C; that for the intermediate generated by iodine (2–6 s) much exceeded the others. The ki value increased in the order: I2 < CH3SO3H ≪ BF3O(C2H5)2 ∼ SnCl4.
TL;DR: A twenty-membered macrocyclic oligoester consisting of alternating tetrahydropyran and ester moieties was prepared selectively by the cationic oligomerization of 6,8-dioxabicyclo[3.2.1]octan-7-one (1) in chloroform at −40°C with boron trifluoride etherate as an initiator as discussed by the authors.
Abstract: A twenty-membered macrocyclic oligoester consisting of alternating tetrahydropyran and ester moieties was prepared selectively by the cationic oligomerization of 6,8-dioxabicyclo[3.2.1]octan-7-one (1) in chloroform at −40°C with boron trifluoride etherate as an initiator. The solubility data of ten-, twenty-and thirty-membered cyclic oligomers of 1 in four different solvents, along with the significant time dependence of the product distribution, indicate that the formation of these cyclic oligomers is controlled primarily by solubility and kinetic factors.
TL;DR: In this paper, alternating copolymerization of 2-acryloxypropionic acid (APA) as a new MN with two MN monomers of phosphorus containing ethylene phenyl phosphonite (EPO) and ethylene Phenyl phosphite (EPI) have been disclosed.
Abstract: Alternating copolymerization of 2-acryloxypropionic acid (APA) as a new MN with two MN monomers of phosphorus containing ethylene phenyl phosphonite (EPO) and ethylene phenyl phosphite (EPI) have been disclosed. Copolymerizations took place without added catalyst to produce 1∶1 alternating copolymers of APA-EPO and of APA-EPI. The structures of the copolymers were determined by IR and NMR spectroscopy, elemental analyses, as well as the identification of the alkaline hydrolysis products. The copolymerizations were explained in terms of a mechanism of zwitterion intermediates involving a hydrogen transfer process.
TL;DR: In this paper, a conductance study was carried out for polyelectrolyte-catalysed complexation reaction of Ni2+ with murexide, and the result was compared with the ordinary stopped-flow method and excellent agreement was obtained.
Abstract: Conductance stopped-flow study was carried out for a polyelectrolyte-catalysed complexation reaction of Ni2+ with murexide. The result was compared with the ordinary stopped-flow method and excellent agreement was obtained, showing reliability of the conductance method.