A comparison of various ionic surfactant modifiers used in in situ synthesis of organo-montmorillonite inside wood flour

- In most cases, WF was successfully modified by Na+-Mt and surfactant modifiers.
- OMt reduced the hygroscopicity and improved the mechanical property of WF.
- Cationic surfactant modifiers performed better than the anionic ones.
- DDAC performed the best among all modifiers.

In this study, organo-montmorillonite (OMt) was in situ synthesized inside the wood flour (WF) by using sodium-montmorillonite (Na+-Mt) and ionic surfactant modifiers as raw materials. Six different surfactants, including didecyl dimethyl ammonium chloride (DDAC), dodecyl dimethyl benzyl ammonium chloride (BAC), hexadecyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulfonate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium stearate (SSTA) were selected for a comparative analysis. The thus-modified WF samples were characterized. Their hygroscopicities and mechanical properties were tested. The results showed that: (1) in most groups, Na+-Mt transformed to OMt and uniformly distributed in WF cell wall, forming intercalated structures; (2) in most groups, OMt reduced the hygroscopicity of WF as well as improved the modulus of elasticity and hardness significantly; (3) DDAC and SDS were the best cationic and anionic surfactant modifiers in modified Na+-Mt, respectively. Compared with the anionic surfactant modified groups, cationic ones were better.