Preparation And Applications Of Nanocellulose/Jatropha Oil Based Polymer Composite Emulsions As Leather Fatliquors

Polymer fatliquors have attrated increasing research interest in the leather industry due to its strong interactions with collagen fibers,solvent-resistance and fullness of leather.However,such polymer fatliquors are mainly derived from non-renewable and nondegradable petroleum-based resources.Therefore,it is necessary to develop biomass-based polymer fatliquors.In this thesis,Jatropha oil was used as raw material to prepare jatropha oil-based polymer fatliquor(AEJO-AA)by chemical modification.At the same time,Nano-cellulose(CNC)was modified to prepare dialdehyde nanocellulose(DNC)and alkylated nanocellulose(M-CNC),and then DNC and M-CNC were introduced into the AEJO-AA matrix by physical blending or in-situ polymerization,respectively.The effect of DNC and M-CNC on the mechanical properties,thermal stability,softness,thickening rate and fogging value of the fatliquored leather was studied.The detailed research contents and results are shown as follows:(1)Jatropha oil acrylate(AEJO)was obtained by two-step method of “epoxidation” followed by “acrylation”.Subsequently,an amphiphilic polymer emulsion AEJO-AA was prepared with emulsion polymerization using acrylic acid(AA)and AEJO.AEJO-AA emulsion was then used as a fatliquoring agent of goatskin leather.The fatliquored leather had a softness of 7.4 mm,a thickening rate of 49%,and a fogging value of 4.83 mg,which exhibited a good fatliquoring effect,but the physical and mechanical strength was lower than that of the leather treated by commercially petroleum-based fatliquor.(2)2,3-dialdehyde nanocellulose(DNC)was prepared with oxidation method using nanocellulose as raw material,and then as reinforcement and crosslinker introduced into AEJO-AA polymer fatliquor to improve the physical and mechanical properties,and thermal stabilities of the goatskin upper leather.The nanocomposite fatliquor(DNC/AEJO-AA)with different DNC loadings was prepared by physical blending method.As the DNC loading was 1.5 wt%,the fatliquored leather exhibited the highest tensile strength of 24.3 MPa,tear strength of 62.2 N/mm and thermal denaturation temperature of 95.4 °C,and the fogging value of the fatliquored leather satisfy the requirements of automobile seat leather.(3)The alkylated nanocellulose(M-CNC)was prepared by alkylation of nanocellulose with silane coupling agent(KH-570).After that,M-CNC was introduced into AEJO-AA polymer fatliquor matrix by in-situ polymerization and its dosage was optimized.The transmission electron microscopy(TEM)results showed that M-CNC was completely wrapped on the surface of the latex particles,and the particle size of the latex particles gradually decreases with the increase of M-CNC loading,furthermore,the surface roughness of the latex particles gradually increased.After being applied in the leather fatliquoring process,the fatliquored leather exhibited obviously improved mechanical strength and thermal stability,and the distribution of the fatliquor in the leather was relatively uniform.When the loading of M-CNC was 2.0 wt%,the fatliquored leather exhibited the highest tensile strength of 18.4 MPa,tear strength of 53.2 N/mm,and the fogging values of the fatliquored leather also satisfy the requirements of automobile seat leather.