High Pressure Compression-Molding of α-Cellulose and Effects of Operating Conditions

Abstract

Commercial α-cellulose was compression-molded to produce 1A dog-bone specimens under various operating conditions without any additive. The resulting agromaterials exhibited a smooth, plastic-like surface, and constituted a suitable target as replacement for plastic materials. Tensile and three-points bending tests were conducted according to ISO standards related to the evaluation of plastic materials. The specimens had strengths comparable to classical petroleum-based thermoplastics. They also exhibited high moduli, which is characteristic of brittle materials. A higher temperature and higher pressure rate produced specimens with higher mechanical properties while low moisture content produced weaker specimens. Generally, the strong specimen had higher specific gravity and lower moisture content. However, some parameters did not follow the general trend e.g., thinner specimen showed much higher Young’s Modulus, although their specific gravity and moisture content remained similar to control, revealing a marked skin-effect which was confirmed by SEM observations.

The pressure–volume–temperature relationship of cellulose

“…No crystallization temperature has ever been observed for cellulose, but Vaca-Medina et al (Accepted) showed an increase in the crystallinity index of a-cellulose during compression at higher temperatures. Moreover, Pintiaux et al (2013) have tested the mechanical properties of the thermo-compressed samples, and demonstrated an increase in these properties with temperature. Therefore during thermo-compression, crystallization must be associated with another phenomenon responsible for consolidating the powder.…”

“…Production of bulk cellulose plastic has been investigated recently using a specific high shear and high-pressure device (Zhang et al 2011), a multi-step non-solvent approach (Nilsson et al 2010), or direct compression on cotton linters (Navard 2012). Our group has studied the influence of the compressing operating conditions on a-cellulose compressed materials (Pintiaux et al 2013), and the effect of temperature on the compression of various celluloses (Vaca-Medina et al Accepted).…”

Partial periodate oxidation and thermal cross-linking for the processing of thermoset all-cellulose composites

“…Very recently, ACCs obtained by compression molding of a-cellulose (i.e. similar to MCC) at very high pressure (>100 MPa) and high temperature (>150 C) exhibit specimens with flexural modulus also around 7 GPa but flexural strength of 43 MPa [39]. These values emphasize the key role of the chemical bonding between the cellulose nanocrystals, and denote effective stress transfer within the material.…”

A Solvent-Free Approach for Production of Films from Pectin and Fungal Biomass

“…However, the solution casting method, the most-commonly used method for pectin film production, has a high demand of energy. In this work heat compression molding technique, with lower energy demand compared to casting [27,28], was employed for production of pectin films. Furthermore, the potential of the fungal biomass for enhancement of the pectin films was investigated.…”