Bio‐Based Nanocomposites of Cellulose Acetate and Nano‐Clay with Superior Mechanical Properties

Abstract

Summary: Bio‐based nanocomposites were manufactured by melt intercalation of nanoclays and cellulose acetate (CA) with and without plasticizer. Glycerol triacetate (triacetin) as plasticizer up to 30 mass%, and different types of organo‐modified and unmodified montmorillonites (MMTs) as filler were used. X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), were used to study clay dispersion, intercalation/exfoliation, and structure of the composites. XRD and TEM revealed very good dispersion and exfoliation of modified clay throughout the CA matrix. While for unmodified clay agglomeration and poor dispersion but an intercalated structure was observed. The mechanical properties of injection moulded test bars were determined by a tensile experiment giving tensile strength, Young's modulus and elongation at break. Adding plasticizer facilitated the processing and up to 20 mass%, increased the tensile strength, Young's modulus and elongation at break as well. Higher amount of plasticizer diminished the tensile properties except elongation showing a slight increase. In all plasticized composites, organo‐modified clay improved the tensile strength and at the same time, young's modulus and elongation almost remained constant. On the other hand, plasticized CA compounded with unmodified clay revealed lower properties. In a particular case, compounding of unplasticized CA with unmodified clay resulted in superior mechanical properties with a novel structure. So that, in optimum percentage –5 mass%‐ of unmodified clay, tensile strength and young's modulus increased significantly by 335% and 100%, to 178 MPa and 8.4 GPa, respectively. This is a dramatic improvement in strength and stiffness of CA. Adding organo‐modified clay resulted in a little improvement in tensile properties. SEM pictures of the optimum composite showed a core/shell structure with high orientation in the shell part. It is supposed that this behaviour is caused by the interaction between CA hydroxyl groups and free cations existing in the galleries of unmodified clay.

Development of Cellulose Eco‐nanocomposites with Antimicrobial Properties Oriented for Food Packaging

“…These fractures look more brittle, and no plasticity of matrix polymer can be evidenced. Similar fracture morphologies have also been reported by other authors to CA nanocomposites . The use of a higher content of plasticizer (>20 wt%) has been reported as an alternative to solve the brittle problem in this kind of this material …”

“…In studies carried out by other authors, CA, TEC and organically modified clay nanofillers produced an intercalated nanocomposite that showed important changes on the mechanical properties. Glycerol triacetate was also used as plasticizer up to 30 mass% in CA nanocomposites based on different organoclays . X‐ray diffraction (XRD) patterns and TEM revealed a very good dispersion and exfoliation of modified clay throughout the CA matrix, which explained important changes on the mechanical properties of these nanocomposites.…”

Fabrication and Characterization of Cellulose Acetate/Montmorillonite Composite Nanofibers by Electrospinning

“…As expected, the increase in the conductivity of CA/MMT with higher MMT concentrations caused a significant decrease in the diameter of the CA/MMT nanofibers. The extent of MMT intercalation and dispersion can be usually obtained from the WAXS and TEM results [21]. Figure 4 shows the XRD patterns of MMT, CA, and CA/MMT nanofibers with different MMT contents.…”

Toughening of electrospun poly(l-lactic acid) nanofiber scaffolds with unidirectionally aligned halloysite nanotubes

“…Because of its good biocompatibility and low cost, HNTs have attracted increasing interests of researchers due to their unique advantages. HNTs have been demonstrated to be an ideal reinforcement agent for fabricating polymeric composites with improved mechanical performance [14]. Recently, several types of HNTfilled composite nanofibers have been successfully produced.…”