Chemical resistance

About: Chemical resistance is a(n) research topic. Over the lifetime, 3115 publication(s) have been published within this topic receiving 19059 citation(s).

Composite material containing a layered silicate

Abstract: A composite material comprising a resin other than polyamide resin and a layered silicate dispersed therein, said layered silicate having a layer thickness of 7 to 12 Å and an interlayer distance of 30 Å or above. Owing to the layered silicate uniformly dispersed in the resin matrix, the composite material is superior in mechanical characteristics and heat resistance. It also has good water resistance and chemical resistance.

Tannin-based rigid foams: a survey of chemical and physical properties.

Abstract: Tannin-based rigid foams, prepared from 95% natural material, are suggested for replacing synthetic phenol-formaldehyde foams in various applications. For that purpose, a few physical properties were measured and reported here: resistance to fire and chemicals, absorption of various liquids, permeability, thermal conductivity and mechanical (compressive and tensile) strength. Modifying the composition through the use of boric and/or phosphoric acid allowed substantial increase of fire resistance. The materials were also found to present good resistance to strong acid and bases, and to solvents. High affinity for water, but limited one for organic liquids, was also evidenced. Finally, slightly anisotropic mechanical properties were measured. The materials present a brittle behaviour, whether tested in compression or traction; nevertheless, their strengths, as well as their thermal conductivities, are fully comparable with those of their phenolic counterparts. We show that such materials of vegetable origins can compete with synthetic ones for most of traditional applications.

Syndiospecific polymerization of styrene

Abstract: Syndiotactic polystyrene, namely XAREC® is being developed by Idemitsu Petrochemical Co., Ltd. as a major new polymer family. XAREC® is a new crystalline engineering thermoplastic with a crystalline melting point of 270 °C. Because of its crystalline nature, XAREC® has a high heat resistance, an excellent chemical resistance and a water/steam resistance. XAREC® also has the dip soldering resistance. Potential applications for XAREC® include surface-mount electronic devices and electrical connectors. In this paper, some mechanistic models for polymerization and stereo-regulation as well as the factors which affect the activity and stereospecificity of the catalysts are discussed. The effects of substitutions on Cp ligand of half titanocene complexes were examined. The bulky substitution groups reduce the activity. Also, borate compounds as activator and effects of hydrogen are discussed.

Inorganic pigments composition having high hardness

Abstract: Disclosed is a high-hardness inorganic coating composition which is capable of forming a coating film having high hardness, antibacterial activity, water resistance, chemical resistance and non-flammability, and exhibiting superior adhesion to a substrate, on a metal or non-metal surface. The present invention provides the high-hardness inorganic coating composition which is prepared by mixing a binder and an inorganic filler in water.

Castor oil-based hyperbranched polyurethanes as advanced surface coating materials

Abstract: 21st Century is treated as the century for highly branched macromolecules, because of their unique structural architecture and outstanding performance characteristics, in the field of polymer science. In the present study, castor oil-based two hyperbranched polyurethanes (HBPUs) were synthesized via A2 + B3 approach using castor oil or monoglyceride of the castor oil as the hydroxyl containing B3 reactant and toluene diisocyanate (TDI) as an A2 reactant along with 1,4-butane diol (BD) as the chain extender and poly(ɛ-caprolactone) diol (PCL) as a macroglycol. The adopted ‘high dilution and slow addition’ technique offers hyperbranched polymers with high yield and good solubility in most of the polar aprotic solvents. Fourier transforms infra-red spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed the chemical structure of synthesized polymers, while wide angle X-ray diffraction (WXRD) and scanning electron microscope (SEM) resulted the insight of their physical structures. The degree of branching was calculated from 1H NMR and found to be 0.57 for castor oil based hyperbranched polyurethane (CHBPU), while it was 0.8 for monoglyceride based hyperbranched polyurethane (MHBPU). The studies showed that MHBPU and CHBPU exhibited tensile strength 11 MPa and 7 MPa, elongation at break 695% and 791%, scratch hardness 5 kg and 4.5 kg, gloss 84 and 72, respectively. Thermal properties like thermo stability, melting point, enthalpy, degree of crystallinity and glass transition temperature (Tg); and chemical resistance in different chemical media were found to be almost equivalent for both the polyurethanes. The measurements of dielectric constant and lost factor indicated that both the HBPUs behave as dielectric materials. Thus the synthesized HBPUs have the potential to be used as advanced surface coating materials.