Biodegradation of poly(vinyl alcohol) based materials

Binder Jet printing is an additive manufacturing technique that dispenses liquid binding agent on powder to form a two-dimensional pattern on a layer. The layers are stacked to build a physical article. Binder Jetting (BJ) can be adapted to almost any powder with high production rates and the BJ process utilizes a broad range of technologies including printing tehniques, powder deposition, dynamic binder/powder interaction, and post-processing methods. A wide variety of materials including polymers, metals, and ceramics have been processed successfully with Binder Jet. However, developing printing and post-processing methods that maximize part performance is a remaining challenge. This article presents a broad review of technologies and approaches that have been applied in Binder Jet printing and points towards opportunities for future advancement.

Binder jetting: A review of process, materials, and methods

A resin composition for toners which comprises a vinyl copolymer obtained mainly from a styrene monomer and a (meth)acrylic ester monomer, a Fischer/Tropsch wax, and a polystyrene block copolymer, characterized in that the vinyl copolymer has a molecular weight distribution as determined by gel permeation chromatography in which at least two peaks are present respectively in the molecular-weight region of from 5,000 to 20,000 and the region of molecular weights not lower than 500,000, that the wax is contained in an amount of 2 to 10 wt.%, and that the block copolymer is contained in an amount of 0.5 to 5 wt.%; and a toner containing the resin composition.

Resin composition for toner and toner

Effect of starch type on the properties of starch containing films

Poly(vinyl alcohol) (PVA) was blended with 10, 20, 30, 40, and 50 wt % of starch with and without crosslinking by solution casting process. The solution-casted films were dried and tested for physicomechanical properties like tensile strength, tensile elongation, tensile modulus, tear and burst strengths, density, and thermal analysis by differential scanning calorimetry (DSC). These PVA/starch films were further characterized for moisture content; solubility resistance in water, 5% acetic acid, 50% ethanol, and sunflower oil; and swelling characteristics in 50% ethanol and sunflower oil. The crosslinked PVA/starch composite films show significant improvement in tensile strength, tensile modulus, tear and burst strengths, and solubility resistance over the uncrosslinked films. Between the crosslinked and uncrosslinked films, the uncrosslinked films have higher tensile elongation, moisture content, moisture absorption, and swelling over the crosslinked films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 909–916, 2007

Crosslinked poly(vinyl alcohol) and starch composite films. II. Physicomechanical, thermal properties and swelling studies

PURPOSE: To obtain ink jet recording paper of high resolving power by using a polymer emulsion prepared by the emulsion polymerization of an ethylenic unsaturated monomer or diene type monomer using a polyvinyl alcohol polymer having a mercapto group at its terminal as a dispersion stabilizer as a surface sizing agent or a surface coating pigment binder agent. CONSTITUTION: A polymer emulsion prepared by the emulsion polymerization of an ethylenic unsaturated monomer {e.g. methyl (meth)acrylate} or diene type monomer (e.g. butadiene) using a polyvinyl alcohol polymer having a mercapto group at its terminal as a dispersion stabilizer is used as a surface sizing agent or a surface coating pigment binder. As a result, ink jet recording paper forming a recording image high in resolving power and excellent in water resistance can be obtained. COPYRIGHT: (C)1995,JPO

Ink jet recording paper

Properties of aqueous solutions of blends of starch and polyvinyl alcohols (PVAs), having alkyl groups as side chains, or at one polymer chain end, were studied in terms of viscosity stability, and transparency. In the case of corn starch, PVAs having butyl, octyl, and dodecyl end groups, as well as PVA copolymers containing small amounts of vinyl versatate, together with itaconic acid, increased the stability of the blended solution. The aqueous solutions of PVA, having dodecyl end groups and oxidized starch blend, also showed good stability in viscosities and considerable increase in transparency, whereas conventional PVA and oxidized starch blend gave turbid aqueous solutions, followed by phase separation. The phenomena were assumed to arise from the interaction of the alkyl group in PVA with starch, forming a helical structure with the alkyl group in the hydrophobic internal part.

Specific interaction of starch and polyvinyl alcohols having long alkyl groups

Poly(vinyl alcohol) (PVA) and poly(vinyl acetate) having a thiol group at one end were synthesized by free-radical polymerization of vinyl acetate in presence of thioacetic acid as a chain transfer agent followed by treating with sodium hydroxide/methanol and ammonia, respectively. It was found that block copolymers containing the PVA sequence as one constituent were obtained by the redox-initiated polymerization of some vinyl monomers, for example, acrylic acid (AA) and acrylamide (AAm), using PVA having a thiol end group as reductant and an oxidant such as potassium bromate and potassium persulfate.

Synthesis of poly(vinyl alcohol) having a thiol group at one end and new block copolymers containing poly(vinyl alchohol) as one constitent

PROBLEM TO BE SOLVED: To provide a living radical polymerization initiator system which can produce a radical polymer with a controlled molecular weight and a narrow molecular weight distribution easily within a short time and can easily remove a transition metal complex from the polymerization solution. SOLUTION: The living radical polymerization initiator system comprises component (A): a phosphine compound being a triarylphosphine compound [wherein at least one of the aryl groups is represented by formula (2) (wherein R 4 is an optionally branched 1 to 4C alkylene group; R 5 is an optionally branched 1 to 25C alkyl group; and n is a number-average degree of polymerization)], component (B): an organohalogen compound, and component (C): a halogenopentamethlcyclopentadienylruthenium tetramer or a halogenpentamethylcyclopentadienylbis(triarylphosphine)ruthenium. COPYRIGHT: (C)2005,JPO&NCIPI

Living radical polymerization initiator system and process for producing polymer by using the same

In dispersion polymerization of styrene in ethanol, effects of a reactive steric stabilizer, poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group (P(VAc/VA)-SH), were investigated. In the absence of the thiol end group, the dispersion coagulated at the middle stage of the polymerization, while in the presence of the thiol end group, the polymerization proceeded successfully to result in close to monodisperse particles. The reactive thiol group acts as a site of formation of the block copolymer, that is, polystyrene-b-P(VAc/VA), which is utilized as an effective dispersant. From the measurement on molecular weights during the course of polymerization, two polymerization loci were realized. Addition of butyl methacrylate to styrene affected markedly not only rate of polymerization but also particle size. © 1996 John Wiley & Sons, Inc.

Kazutoshi Terada

Papers

Ink jet recording paper

Specific interaction of starch and polyvinyl alcohols having long alkyl groups

Synthesis of poly(vinyl alcohol) having a thiol group at one end and new block copolymers containing poly(vinyl alchohol) as one constitent

Living radical polymerization initiator system and process for producing polymer by using the same

Effect of poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group as a steric stabilizer on dispersion polymerization of styrene