TITLE:
Importance of Dynamic Mechanical Analysis to Predict Performance of the Polyvinyl Acetate Wood Adhesives in Summer Season
AUTHORS:
Ravindra V. Gadhave
KEYWORDS:
Polyvinyl Acetate, Wood, Adhesive, Cracking, Dynamic Mechanical Analysis
JOURNAL NAME:
Open Journal of Polymer Chemistry,
Vol.12 No.3,
August
31,
2022
ABSTRACT: Conventionally available Polyvinyl acetate (PVAc)
wood glues are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor
strength at high humidity, poor strength at high temperature and workability at
low-temperature. PVAc is non-resistant to high humidity, and if such adhesive
bonds are exploited in a highly humid environment, its strength substantially
decreases. Sufficiently water-resistant adhesive bonds are achieved by
modifying PVAc dispersion with special
chemicals like acrylic acid (AA) and N-methylol acrylamide (NMA) as a
co-monomer, Silanes, and ethylene modified PVA. The Lewis acids like aluminium
chloride and aluminium nitrate are used as cross-linkers. So PVAc
adhesives are classified as reactive and non-reactive glue. Application of non-reactive
D1 (as per EN 204-205) and reactive D2 and D3 (as per EN 204-205) adhesives for
bonding laminate on plywood is a regular practice in the Indian market. In
summer time, Crack formation was seen in laminate bonded with reactive D2 and
D3 adhesives in regions where the room temperature was above 45°C. However, if
the same laminate substrates were bonded with non-reactive D1, no cracks were
seen. To analyse the above phenomenon, we have done Dynamic mechanical analysis
of non-reactive D1, reactive D2 and D3 adhesive.