Cellulose Nanocrystals (CNCs) Induced Crystallization of Polyvinyl Alcohol (PVA) Super Performing Nanocomposite Films

Abstract

This study is aimed to explore the properties of cellulose nanocrystals (CNC)/polyvinyl alcohol (PVA) composite films with and without 1,2,3,4‐butane tetracarboxylic acid (BTCA), a nontoxic crosslinker. CNC and CNC‐PVA nanocomposite films are prepared using solution‐casting technique. Differential scanning calorimetry (DSC) analyses show that crosslinking increased the glass transition temperature but reduced the melting temperature and crystallinity. Furthermore, high CNC concentrations in the PVA matrix interfere with PVA crystallinity, whereas in specific ratio between CNC and PVA, two different crystalline structures are observed within the PVA matrix. Film surfaces and fracture topographies characterized using scanning electron microscope indicate that at certain CNC‐PVA ratios, micron‐sized needle‐like crystals have formed. These crystalline structures correlate with the remarkable improvement in mechanical properties of the CNC‐PVA nanocomposite films, that is, enhanced tensile strain and toughness to 570% and 202 MJ m−3, respectively, as compared to pristine PVA. BTCA enhances the tensile strain, ultimate tensile stress, toughness, and modulus of CNC films compared to pristine CNC films. Water absorption of crosslinked CNC and CNC‐PVA nanocomposite films is significantly reduced, while film transparency is significantly improved as a function of PVA and crosslinker content. The presented results indicate that CNC‐PVA nanocomposite films may find applications in packaging, and though materials applications.

Preparation of treelike and rodlike carboxymethylated nanocellulose and their effect on carboxymethyl cellulose films

“…2,45 However, agglomeration of nanocellulose will take place after incorporating excessive content to matrix, resulting in TS decrease. 46,47 From the Figure 3(b), we observed that adding nanocellulose decreases the EB of composite films and the negative effect of CMCNCs on the toughness of the composite film is greater than that of CMCNFs at the same time. Generally, to increase the TS by adding rigid filler is at the cost of toughness.…”

Cellulose Nanocrystals and Corn Zein Oxygen and Water Vapor Barrier Biocomposite Films

“…CNC is one of the most suitable materials for enhancing properties of composite materials [ 15 , 16 ]. CNC, consistent with the required food packaging features especially strength and barrier properties, however, One notable disadvantage of CNC is its low resistance to moisture and in the deterioration in mechanical properties of films made from CNC when exposed to moisture [ 17 , 18 , 19 , 20 ].…”

“…Carboxylic acids, particularly polycarboxylic acid, have been shown to be good cellulose crosslinking agents [ 32 , 33 , 34 ]. SHP is a most effective catalyst for catalyzing a reaction with BTCA [ 35 ] in a previous paper we demonstrate the effect of BTCA on CNC and CNC-poly vinyl alcohol film properties [ 16 ]. This nontoxic crosslinking method serves the textile industry in crosslinking cotton cellulose to improve anti-pilling, wrinkle recovery, antimicrobial, water repelling, and flame-retarding properties of the cotton fabric [ 36 ].…”

“…The non-crosslinked films exhibited excellent film flexibility but poor barrier ability and water absorption capacity, while crosslinked films showed good performance in both properties although the contact angel of the non-crosslinked films was higher, probably because of the unique arrangement of the films surface, as characterized by SEM and AFM. The objective of this study was to evaluate and characterize the films barrier, mechanical, optical and thermal properties of CNC/CZ based film as affected by the composition of “green” and nontoxic cross linker, a method developed in our previous publication [ 16 ].…”

Changes in Crystallization Behaviors of Poly(Vinyl Alcohol) Induced by Water Content

“…[ 12 ] Ben Shalom et al prepared PVA/cellulose nanocrystals (CNCs) nanocomposite and found that CNC acting as a nucleating agent could increase the crystallinity of PVA at a low CNC content. [ 13 ] He et al fabricated PVA/graphitic carbonitride (g‐C 3 N 4 ) nanocomposites by solution casting method. The results showed that the glass transition temperature, crystallinity, and mechanical performance of PVA were enhanced by the introduction of g‐C 3 N 4 nanosheets.…”