Pre-mixing and masterbatch approaches for reinforcing poly(vinyl acetate) with cellulose based fillers

Milling of microcrystalline cellulose (gMCC) and poly(vinyl acetate) (gPVAc) was performed, and the milled samples were pre-mixed prior to melt-mixing. Ground samples that were pre- and subsequently melt-mixed (gPVAc/gMCC) showed similar reinforcement (modulus of ∼3 GPa at 25 °C, ∼9 MPa at 90 °C) compared to the directly mixed composites containing cellulose nanocrystals isolated by acid hydrolysis from cotton (PVAc/CNC, modulus of ∼3 GPa at 25 °C and ∼10 MPa at 90 °C). Highly concentrated masterbatches (up to 60 wt% of gMCC) are shown for the first time with cellulosic filler. These additive concentrates can be first prepared using a solution casting approach, aiding in efficient transport, and then diluted by melt-mixing when needed. Using DMF and water as solvents for preparation, melt-processing schemes that are easier to scale-up and exploit industrially were evaluated in this work.