A Combined Theoretical and Experimental Study of the Polymer Matrix-Mediated Stress Transfer in a Cellulose Nanocomposite

Abstract

We study composites of cellulose nanocrystals (CNCs) in an ionomer matrix of poly(ethylene-stat-sodium acrylate) and find that direct cellulose/cellulose interactions in the composite are not a requirement for achieving reinforcement. While isotropic composites only show a slightly enhanced stiffness compared to the neat ionomer, a more substantial increase in Young's modulus by a factor of up to 5 is achieved by uniaxial alignment of the composites through melt spinning. The orientation of CNC in melt-spun composites reduces the probability of cellulose/ cellulose interactions, which suggests that cellulose/polymer interactions must be present that lead to the observed reinforcement. Molecular dynamics simulations confirm strong cellulose/polymer interactions in the form of ionic interactions as well as hydrogen bonding. These cellulose/polymer interactions facilitate efficient stress transfer, leading to the high reinforcing effect of CNC, while cellulose/cellulose interactions play a minor role in the mechanical response of the composite.

Water‐assisted melt processing of cellulose biocomposites with poly(ε‐caprolactone) or poly(ethylene‐acrylic acid) for the production of carton screw caps

“…The presence of polar acrylic acid groups on the EAA7 chains make the polymer relatively more hydrophilic and thus improve the EAA7-CNC compatibility. 10,18 The poorer adhesion between PCL and CNC is also reflected in the higher surface roughness of the PCL-based composites.…”

“…Poly(ethylene-co-acrylic acid) (EAA) is a copolymer commonly used in the packaging industry, containing acrylic acid groups, providing good adhesion with a hydrophilic reinforcement. 10,[16][17][18] As biodegradable alternative to EAA, poly(ε-caprolactone) (PCL) was selected considering its biodegradability, high ductility, and toughness, but with a relatively more hydrophobic surface than the EAA. 19 Both matrices have relatively low melting points thus enabling more effective water-assisted extrusion and the possibility of low processing temperatures, which are beneficial to prevent cellulose degradation.…”

Tailoring Interfacial Adhesion between PBAT Matrix and PTFE-Modified Microcrystalline Cellulose Additive for Advanced Composites

“…When the PTFE addition was 0.5%, the maximum value of φ was 0.98, which was very close to 1, indicating that 0.5#MCC and PBAT had very high interfacial adhesion strength, which was consistent with the results observed by SEM and mechanical performance. Thus, it can be concluded that strong cellulose/polymer interaction is conducive to stress transfer and enhance mechanical properties [ 37 ].…”

Machine-Learning-Assisted Design of Highly Tough Thermosetting Polymers

“…Machine Learning. (1) The dimensionality reduction model based on the GCN + a + g and MLP was implemented using Python and the TensorFlow framework. 67 This model was trained with a learning rate of 0.001 and a decay of 0.95 using a minibatch size of 50 and the Adam optimizer.…”