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

• Highly concentrated polymer masterbatches containing cellulose filler (up to 60 wt%) are shown for the first time.
• Dilution of highly filled masterbatch retains the reinforcement as of the pre-mixed composites.
• Milling of MCC could provide an industrially more relevant filler for upscaling the production of cellulose filled composites.

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.