Shin-ichiro Ishida

Organic hybrid of chlorinated polyethylene and hindered phenol. I. Dynamic mechanical properties

Dynamic mechanical properties and microstructure of an organic hybrid consisting of chlorinated polyethylene (CPE) and 3,9-bis[1,1-dimethyl-2{β-(3-tert-butyl4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) were investigated. The AO-80 clearly exhibited two second-order transitions at 6 and 69 °C in addition to the melting: the transition at lower temperature is assigned to the glass transition, and the transition at higher temperature is considered to be caused by the dissociation of hydrogen bond between the hydroxyl groups of AO-80. When blending with CPE, part of AO-80 molecules was dispersed into the CPE matrix, and most of them formed an AO-80-rich phase. As a result, a novel transition appeared above the glass-transition temperature of the CPE matrix. It was assigned to the dissociation of the intermolecular hydrogen bond between the α-hydrogen of CPE and the hydroxyl groups of AO-80 within the AO-80-rich phase. Dynamic mechanical properties and microstructure of CPE/AO-80 hybrid were controlled by the thermal treatment. It was found that the CPE/AO-80 hybrid is a good damping material and shows a shape memory effect.

Organic hybrid of chlorinated polyethylene and hindered phenol. II. Influence of the chemical structure of small molecules on viscoelastic properties

The viscoelastic properties and stabilities of those properties of organic hybrids consisting of chlorinated polyethylene (CPE) and tetrakis[methylene-3-(3-5-di-tert-butyl-4-hydroxy phenyl)propionyloxy]methane (AO-60) and triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methyl phenyl)propionyloxy] (AO-70) were investigated. The CPE/AO-70 hybrids show only one transition, whereas for the CPE/AO-60 hybrids, one novel relaxation appears above the glass-transition temperature of CPE. This relaxation on the higher temperature side in the mechanical spectrum for CPE/AO-60 is associated with the appearance of the AO-60-rich phase. Furthermore, the stabilities of the viscoelastic properties and microstructures of the organic hybrids consisting of CPE and multifunctional hindered phenols are dominated by the strength of the intermolecular interaction between CPE and phenols and the conformations of the middle skeletal parts of hindered phenols.

Viscoelastic properties of an organic hybrid of chlorinated polyethylene and a small molecule

The dynamic mechanical properties of an organic hybrid consisting of chlorinated polyethylene (CPE) and N,N-dicyclohexyl-2-benzothiazolyl sulfenamide (DZ) were investigated. All the CPE/DZ hybrids showed a single loss tangent (tan δ) peak in the mechanical spectra. The peak area under the tan δ/temperature curves around the mechanical loss peak was examined to characterize the damping properties of the CPE/DZ hybrids. We found that there exists a bending point in the relation between the glass-transition temperature (Tg) and DZ content and that the value of Tg is saturated in the higher DZ contents, suggesting that excess DZ molecules show self-aggregation and are reorganized.

Organic hybrid of chlorinated polyethylene and hindered phenol. III. Influence of the molecular weight and chlorine content of the polymer on the viscoelastic properties

The influences of the molecular weight and chlorine content of chlorinated polyethylene (CPE) on the dynamic mechanical propertiesof an organic hybrid consisting of CPE and 3,9-bis[1,1-dimethyl-2{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) were investigated. All CPE/AO-80 hybrids clearly exhibited two kinds of relaxations, and their magnitudes varied according to the molecular weight and chlorine content of CPE. This was due to a change in the ratio of AO-80 molecules dispersed in the CPE-rich domain and the AO-80-rich domain. A comparison of the jump intensity in differential scanning calorimetry curves with the maximum value of the second tan δ peak demonstrated that the second relaxation was caused by the dissociation of intermolecular hydrogen bonding within the AO-80-rich domain.

Molecular inclusion in calixarenes. XVIII. Crystal and molecular structure of thep-tert-butylcalix[7]arene 1 : 3 pyridine complex/clathrate

The structure of thep-tert-butylcalix[7]arene 1:3 pyridine complex/clathrate (C77H98O7 · 3 C5H5N) has been determined by X-ray crystallography. The crystal data are as follows: monoclinic, space groupP21/c,a = 37.790(4),b = 9.423(2),c = 29.075(4)Å;β = 112.74(2)°;V = 8285(3)Å3;Z = 4;Dcalc = 1.10 g·cm−3. The hostp-tert-butylcalix[7]arene links one pyridine molecule through a hydrogen bond between one of the seven hydroxy groups and the nitrogen of the pyridine. Two other guest molecules have been found in the crystal lattice, so the title compound may be defined as a complex/clathrate hybrid. The unambiguous conformation of the macrocycle is described by an alternative method, which avoids the use of dihedral angles (and the ambiguities in their values).

Characterization of high molecular weight novolak

High molecular weight novolaks were prepared by polycondensation of phenol with paraformaldehyde in acetic acid. The novolak contains soluble, high molecular weight fractions (M w ≥ 10 6 ). The Θ-temperature of the acetylated novolak was determined in 2-ethoxyethanol according to the Shultz-Flory method. The solution viscosity of acetylated and deacetylated novolaks in THF at 25 C and in a Θ-solvent (2-ethoxyethanol at 105°C) was measured, and the molecular dimension in solution was estimated from the parameters of the Mark-Houwink-Sakurada equation. The exponent of 0.24 in THF (good solvent) for acetylated novolak is equal to that in the Θ-solvent. This suggests that the conformation of the novolak is compact like a sphere both in the good and the Θ-solvent. The theoretical value of the exponent in the MHS equation for highly branched polymers is between 0.2 and 0.25 in a Θ-solvent. The exponent for acetylated novolak in the Θ-solvent is close to this value. It is suggested that the acetylated novolak behaves like a highly branched polymer in a Θ-solvent. The 13 C NMR spectrum of novolak confirms that the novolak molecule is a highly branched polymer.

Preparation and characterization of high molecular weight novolak resins

SummaryHigh molecular weight novolak resins were prepared from phenol and paraformaldehyde in organic solvents, e.g., 2-propanol, ethyl propionate, 2-methoxyethanol, 4-methyl-2-pentanone, dioxane and acetic acid. The molecular weights were estimated by gel permeation chromatography (GPC) and solution viscosity measurement and it was confirmed that high molecular weight resins were formed in organic solvents. The structure was determined by13C-NMR measurements, and it was found that the resin obtained in organic solvent was a random novolak with higher molecular weight than a conventional novolak.

A 13C cross polarization–magic angle spinning n.m.r. study of the structure of p-t-butylcalix[4]arene– toluene clathrate in the crystalline state

13 C Cross polarization–magic angle spinning n.m.r. spectra of p-t-butylcalix[4]arene and p-t-butylcalix[4]arene–toluene clathrate in the solid state show that the 13C chemical shift of the methyl carbon of toluene is displaced 6.2 p.p.m. upfield of that of free toluene which agrees well with the calculated value based on the ring current effect of the phenyl groups of the calixarene; the 13C chemical shifts of other carbons were also assigned.

Determination of Mark-Houwink-Sakurada equation for phenolic resins containing alkylenediamine in the main chain and estimation of their molecular conformation in tetrahydrofuran solution

SummaryPhenolic resins containing alkylenediamine in the main chain could be prepared by the co-condensation reaction of phenol, formaldehyde and alkylenediamines such as ethylenediamine and hexamethylenediamine. The molecular structures were determined by1H-NMR spectra, IR spectra and nitrogen content. The molecular conformation of these resins in THF solution were studied from the viscosity measurements, and it became clear that the molecules were considerably compact compared with linear vinyl polymers. To clarify the reason of this phenomenon, the resins whose degrees of branching were different from each other and the resins whose phenolic hydroxyl groups were acetylated were prepared. From viscosity data, it was pointed out that the intramolecular hydrogen bonding contributes to the compaction of the phenolic resins containing alkylenediamine in the main chain more strongly than the branching does.

13C CPMAS NMR study of the structure of p-t-butylcalix[4]arene-alkylbenzene clathrates in the solid state

Abstract The NMR chemical shifts measured by the 13 C CPMAS method for clathrates of p - t -butylcalix[4]arenes including mobile alkylbenzenes in the solid state revealed that the alkyl groups of the guest molecules are located in the cavity of p - t -butylcalix[4]arene, depending on the size of the alkyl group. It was found that n -alkylbenzenes are easily incorporated into p - t -butylcalix[4]arene in the order of toluene > ethylbenzene ⩾ n -propylbenzene. For isopropylbenzene, the bulky isopropyl group prevents incorporation into the cavity of the host molecule.