1、Polyvinyl Alcohol Modification with Sustainable Ketones
During room temperature heterogeneous degradation studies, PV-A-K completely hydrolyzed in 1 day at pH = 2 or in 3 months at pH = 5; after 2 years in deionized water or seawater, ketalization diminished from 69% to 66% (3% hydrolysis).
2、Impact of 10
PVA acetalization by 10-undecenal was carried out in aqueous medium in order to obtain PVA with acetalization degree (AD) ranging from 0.36 up to 1.85 mol%. PVA chain organization in 8 wt% aqueous solutions was investigated through Small Angle X-ray Scattering measurements.
3、Selective acetylation of amorphous region of poly(vinyl alcohol) in
In this study, we achieved the selective acetylation of PVA in the amorphous region alone in sc -CO 2. Interestingly, the highly ordered hierarchical structure, including the crystalline...
Preparation of poly(vinyl alcohol) with enhanced stereoselectivity via
PVAc is prepared by radical polymerization using 7-membered ring controlling agents. PVAc is hydrolyzed to get PVA with enhanced stereoselectivity. Flow chemistry is used to prepare PVAc and its hydrolyzed product PVA. The melting point of PVA was increased by increase in its stereoregularity.
Tailoring polyvinyl alcohol with triazinanes and formaldehyde
Polyvinyl acetals, obtained by the acetalization method, contain strong covalent bonds between the hydroxyl and aldehyde groups to exhibit relatively high water resistance.
Acetalization of poly (vinyl alcohol) by a fatty aldehyde in water
Acid catalyzed poly (vinyl alcohol) (PVA) acetalization was investigated in aqueous medium at 80 °C for a PVA concentration of 8 wt %.
Acetalization of polyvinyl alcohol fibres with glutaraldehyde
The free aldehyde group content of fibres of this type, and their degree of acetalization, are determined by the catalyst concentration, the glutaraldehyde concentration, and the duration and temperature of the treatment.
Kinetics of acetalization of polyvinyl alcohol and of hydrolysis of
Manufacture involves several stages including vinyl acetate polymerization and either sequential or concurrent hydrolysis of poly (vinyl acetate) to poly (vinyl alcohol) and acetalization...
TFCE2206002Akimova
The mechanism of the acetalization reaction and the equations are pro-vided to describe the transformation of polyvinyl alcohol into polyvinyl formal in the presence of formalde-hyde and acid catalysts of the homogeneous and heterogeneous reaction regions.
Influence of Temperature–Time Parameters and System
The mechanism of the acetalization reaction and the equations are provided to describe the transformation of polyvinyl alcohol into polyvinyl formal in the presence of formaldehyde and acid catalysts of the homogeneous and heterogeneous reaction regions.
Polyvinyl acetate (PVAc) is a critical polymeric material widely utilized in textiles, papermaking, adhesives, coatings, and other fields due to its excellent water solubility, film-forming properties, and biocompatibility. In recent years, advancements in science and technology have spurred significant progress in PVAc modification research, with acetalization emerging as an effective approach attracting widespread attention.
Acetalization of Polyvinyl Acetate refers to the process of converting hydroxyl or carboxyl groups in polymer chains into aldehyde groups via condensation reactions. This not only alters the chemical structure of the polymer but also introduces improvements in physical and chemical properties, such as enhanced thermal stability, water resistance, mechanical strength, and sensitivity to specific chemicals.
Selecting an appropriate condensing agent is crucial during PVAc acetalization. Common agents include formaldehyde, glyoxal, and malondialdehyde, which react with hydroxyl or carboxyl groups to form stable acetal bonds. due to formaldehyde’s irritating odor, toxicity, and health hazards, safer and more environmentally friendly alternatives are preferred in practical production.
The methods for PVAc acetalization vary based on application needs. For example, in high-performance coatings, emulsion polymerization can be used to prepare PVAc prepolymers, followed by acetalization with condensing agents to produce superior coatings. For high-strength fibers, solution polymerization can synthesize PVAc homopolymers or copolymers, which are then reinforced via acetalization to improve mechanical properties.
Applications of PVAc Acetalization span diverse industries. In textiles, acetalized PVAc fibers exhibit antistatic and flame-retardant properties, suitable for luxury apparel and home textiles. In adhesives, acetalized PVAc adhesives offer improved bonding strength and wear resistance, ideal for industrial tapes. Additionally, acetalized PVAc is employed in coatings, inks, sealants, and other materials, enriching daily life and industrial innovation.
Research on PVAc acetalization continues to evolve. Scientists enhance product quality by optimizing condensing agent selection, dosage, and reaction conditions. Novel acetalization techniques are also being explored to develop advanced PVAc derivatives with tailored properties.
PVAc acetalization is a potent modification strategy that yields polymers with targeted performance. As technology advances and market demands shift, ongoing research in this field will drive further innovation, contributing to societal progress.
