1、The thermal degradation of poly (vinyl acetate) and poly (ethylene
In this experimental study, a mechanistic investigation is performed on the thermal degradation of PVAc and both semi-crystalline and amorphous EVA with mass percentage vinyl acetate in the polymer backbone ranging from 9 to 73 wt.% in inert and oxidative conditions.
2、On the mechanism of the thermal degradation of polyvinyl acetate
This is due to the accelerating effect of acetic acid. Degradation of PVAc is also accelerated by other acids. There is a certain correlation between the degradation rate and dissociation constants of acids. This indicates that acids accelerate the thermal degradation of PVAc by the ionic mechanism.
3、Mechanism of thermal degradation of poly (vinyl acetate)
The thermal degradation of poly (vinyl acetate) was investigated under dynamic atmosphere of helium up to 400° with a thermobalance. The volatile products were analyzed by a gas chromatograph.
4、(PDF) The thermal degradation of poly (vinyl acetate) and poly
The thermal degradation mechanism of poly (vinyl acetate) (PVAc) and poly (ethylene-co-vinyl acetate) (EVA) copolymers was investigated with solid-state NMR, thermogravimetry coupled with mass spectrometry and differential thermal analysis.
The thermal degradation of poly(vinyl acetate) measured by thermal
In the first stage, 240–310 °C, the thermal degradation of PVAc lead to production of a high proportion of acetic acid. Some aromatic hydrocarbons were also detected. In the second stage (320–370 °C), aromatic hydrocarbons were produced almost exclusively.
The thermal degradation of poly(vinyl acetate) and poly(ethylene
Between 300 and 400 °C acetic acid is eliminated (deacetylation), leaving a highly unsaturated residue or polyene. The deacetylation of PVAc is autocatalytic. Upon incorporation of...
Photochemical degradation study of polyvinyl acetate paints used in
Thermal and photo degradation of PVAc paint samples were studied by Py–GC/MS with double-shot and single-shot techniques. Changes of the PVAc paint samples before and after UV ageing were revealed. The effects of pigments and ageing status to the degradation of PVAc paint samples were illustrated. 1. Introduction.
Char formation in polyvinyl polymers I. Polyvinyl acetate
First degradation step includes acetic acid elimination, forming conjugated double bonds with lower activation energy. Oxidation in air inhibits aromatic condensation, affecting char stability and fire retardancy properties.
5 Poly(vinyl acetate) and related polymers 5.1. Scope 5.2
the production of vinyl acetate directly from ethylene in a one-stage process. In this process ethylene is passed through acetic acid containing sodium acetate, palladiu
On the mechanism of the thermal degradation of polyvinyl acetate
Degradation of polyvinyl polymers (polyvinyl formal, polyvinyl alcohol, and polyvinyl acetate) by high-energy heavy ions was analysed with in situ mass spectrometry and infrared...
In the vast realm of chemistry, countless reactions—simple or complex—collectively form the foundational framework of the material world. Polyvinyl acetate (PVAc), a high-molecular-weight polymer, is widely utilized across various fields due to its unique properties. PVAc is not entirely flawless; under certain conditions, it undergoes decomposition. This process not only reveals the essence of chemical reactions but also provides opportunities to deepen our understanding of material behavior. This article explores the decomposition mechanism of PVAc, the scientific principles behind it, and its practical implications.
As a thermoplastic polymer, PVAc is renowned for its excellent physical and processing properties. its relatively poor chemical stability makes it susceptible to decomposition under external environmental influences. During decomposition, the polymer’s molecular chains break, and new compounds form, altering its original structure and properties. Studying PVAc’s decomposition is therefore critical for understanding aging mechanisms and optimizing material performance.
PVAc decomposition predominantly occurs under conditions of high temperature, humidity, or oxygen exposure. Under such conditions, the ester bonds (-CO-CH₂-) in PVAc may cleave due to thermal or hydrolytic forces, producing small molecules like carboxylic acids and alcohols. These byproducts not only degrade the polymer but also negatively impact its mechanical properties. Controlling decomposition conditions is thus key to maintaining PVAc’s performance in practical applications.
Beyond environmental factors, internal elements—such as molecular weight distribution, crystallinity, and additive use—also influence PVAc’s decomposition behavior. By adjusting these factors, it is possible to inhibit or delay decomposition, thereby extending the material’s lifespan.
The small molecules generated during PVAc decomposition, including acetic acid and acetone, pose environmental and health risks. Appropriate recycling or disposal methods are required to mitigate these impacts. Additionally, studying these byproducts’ properties could enable their utilization or transformation into harmless substances.
PVAc decomposition is a complex process governed by multiple interacting factors. Research in this area advances our knowledge of material aging, improves efficiency, and inspires new synthesis and application strategies. Future efforts should focus on developing novel materials and modifying existing ones to address environmental challenges and market demands.
The decomposition of PVAc, particularly its release of acetic acid, is not merely a chemical reaction but a scientific journey. Through this process, we uncover reaction mechanisms, unlock potential applications for new materials, and drive technological progress. Let us anticipate future breakthroughs that will contribute even greater benefits to society.
