Upcycling Microbial Cellulose Scraps into Nanowhiskers with Engineered Performance as Fillers in All-Cellulose Composites

Abstract

Cellulose is everywhere and renovates in nature continuously and rapidly, while petroleum does not. Unlike the latter, cellulose biodegrades and may represent a carbon sink. Inspired by the multiscale architecture of cellulose, we report on all-cellulose composites comprising cellulose ether as a matrix and highly pure bacterial cellulose nanocrystals (BCNCs) as fillers. Optimum performance as a packaging material was achieved by engineering BCNC surface chemistry as well as the filler-in-matrix dispersion, targeting the replacement of unsustainable, fossil-derived plastics intended for single-use applications. Cost could pose a hurdle, eliminated through the valorization of underutilized scraps from industrial operations, which is also in line with the circular bioeconomy in terms of the integral use of biomass. As far as performance, the optically transparent hydroxypropyl methylcellulose (HPMC) films presented improved tensile strength (from 61 ± 6 to 86 ± 9 MPa) and Young's modulus (from 1.5 ± 0.2 to 2.7 ± 0.4 GPa) while reduced elongation at break (from 15 ± 2 to 12 ± 2%) and water vapor permeability (from 0.40 ± 0.02 to 0.31 ± 0.01 g mm h −1 m −2 kPa −1 ) when filled with only 5 wt % of (120 ± 31) nm long, (13 ± 3) nm wide, 88% crystalline BCNC. This dual, win−win effect of BCNCs on the mechanical and barrier properties of HPMC films was enabled by a suitable dispersion state, achieved via high-energy mixing, and quenched by casting. This study adds to the current literature on all-cellulose composites and helps pave the route for the technical and economical feasibilities of replacing non-renewable, non-biodegradable plastics in short-term applications by materials that are both renewable and biodegradable, that are also produced through green protocols and isolated from surplus biomass, and that still perform similarly or even better.

Fabrication of Noncytotoxic Functional Siloxane-Coated Bacterial Cellulose Nanocrystals

“…The X-ray diffractograms with Rietveld refinement of the pristine and GPTMS- and APTS-functionalized BCNC films (Figure ) evidence a pattern that is typical of type-I cellulose, with the peaks at 14.6°, 16.7°, and 22.7° being assigned, respectively, to the (10), (110), and (200) planes. This pattern is characteristic of the I β (monoclinic) allomorph of cellulose, confirmed by Rietveld refinement, allomorph which prevails in BC. ,, From the Rietveld refinement, it was possible to obtain the lattice parameters, the crystallite size, and the crystallinity index of the films. Those values are shown in Table , together with the weighted profile ( R wp ) and goodness of fit (GOF) criteria of fit.…”

“…The selective hydrolysis of the amorphous domains preserves only the crystalline counterpart, giving rise to nanocrystals with acicular morphology. The so-called bacterial cellulose nanocrystals (BCNC) have been extensively demonstrated to reinforce nanocomposites based on a range of polymers, such as hydroxypropyl methylcellulose, xyloglucan, regenerated chitin fibers, alginate, and poly­(vinyl alcohol) . However, research using BCNC as drug delivery system is still scarce .…”

Current Panorama, Practice Gaps, and Recommendations to Accelerate the Transition to a Circular Bioeconomy in Latin America and the Caribbean

“…In turn, value recovery at the raw material acquisition phase, includes the development of bioactive compounds from agricultural waste [38]. Value recovery at the manufacturing phase includes obtaining chemicals of high added-value from the waste from ethanol production [57], creating new products from whey (a by-product from the manufacturing of dairy products) [61], recovery of biocompounds from black liquor (kraft paper production) [49]; recovery of omega-3 from fish oil [60]; production of chemicals, using fast pyrolysis, from eucalyptus fines [50]; production of biocellulose films from scraps of the commercial production of bandages [51], and biochar from coffee silverskin (from coffee processing units) [66]. Value recovery at the end-of-life phase, in turn, includes recovering phosphorus from eggshell [78] and recovering oil from spent coffee grounds (from coffee shops) [66].…”

The Food–Materials Nexus: Next Generation Bioplastics and Advanced Materials from Agri‐Food Residues

“…Even with geometric restrictions imposed by the inherent production of BC as pellicles (i.e., planar materials), its high strength and water retention capacity have led to many possible applications. For instance, BC pellicles have been directly utilized for, e.g., wound dressing [430,431] and uranium removal. [432] Further engineering of such materials has led to aligned, highly strong (tensile strength ≈800 MPa) BC filaments, [433] as well as optically transparent (transmittance over 80%) and strong (tensile strength ≈1 GPa) films.…”