Thermosets as compatibilizers at the isotactic polypropylene film and thermomechanical pulp fiber interphase

Abstract

The objective of this study was to improve interfacial adhesion properties at the interface of thermomechanical pulp (TMP) fiber and isotactic polypropylene (iPP) using thermoset adhesives such as phenol formaldehyde (PF) and urea formaldehyde (UF). This study also attempted to achieve fiber-to-fiber adhesion using thermoset adhesives before the molten iPP would flow into the fiber web. The fracture surfaces with thermoset adhesive showed identical differences in terms of fracture modes at the interface. An increased TMP fiber failure was observed with increased thermoset quantity at the interface. Using one percent resin content of weight fraction of TMP fiber handsheet, the tensile strength properties increased almost two fold higher than the strength of control samples. Additional adhesive contents of three and five percent showed gradual strength enhancement. However, the enhanced strength was statistically insignificant. UF resin showed slightly better strength performance over PF resin. This result may be caused by solid contents and additional pigments of resins.

Alkyl ketene dimer modification of thermomechanical pulp promotes processability with polypropylene

“…Another example of improving the dispersibility of fibers in PP involves modifying bleached TMP, after co‐precipitation of layered double hydroxide particles with sodium dodecyl sulphate 31 . Urea‐ and phenol‐formaldehyde increases the tensile strength of TMP hand‐sheets and PP films, 32 similar to maleic anhydrate and benzoyl peroxide, and is taken as an indication of improved compatibility between TMP and PP 33 . TMP modified with benzoyl or lauroyl shows good melt and process properties when used as a composite 34 …”