Design and Engineering of Natural Cellulose Fiber-Based Biomaterials with Eucalyptus Essential Oil Retention to Replace Non-Biodegradable Delivery Systems.

This work aims at the design and engineering of sustainable biomaterials based on natural fibers to replace non-renewable fiber sources in the development of non-woven delivery systems. Cellulose fibers were used as the main support to produce multi-structured materials with the incorporation of microfibrillated cellulose (MFC) as an additive. A 3D carboxymethylcellulose matrix retaining a natural bioactive product, eucalyptus essential oil, (CMC/EO), with controlled release functionalities, was also applied to these materials using bulk and spray coating methodologies. Additionally, using a 3D modeling and simulation strategy, different interest scenarios were predicted to design new formulations with improved functional properties. Overall, the results showed that MFC provided up to 5% improved strength (+48%) at the expense of reduced softness (-10%) and absorbency (-13%) and presented a good potential to be used as an additive to maximize natural eucalyptus fibers content in formulations. The addition of CMC/EO into formulations' bulk revealed better strength properties (21-28%), while its surface coating improved absorption (23-25%). This indicated that both application methods can be used in structures proposed for different sustainable applications or a more localized therapy, respectively. This optimization methodology consists of a competitive benefit to produce high-quality functionalized biomaterials for added-value applications.

Challenges in computational materials modelling and simulation: A case-study to predict tissue paper properties.

The growing demand for tissue papers worldwide encourages the paper industry to find new approaches to optimize the raw materials furnish management, and simultaneously to improve tissue paper performance. Softness, strength, and absorption are the key tissue properties that enhance the attention of both industry and consumers. Fiber morphology, fiber modification process steps, and structural properties affect these functional properties, and, therefore, the efforts to evaluate them and establish the relationship or models that describe them constitute a multifactorial challenge. For this purpose, we aimed to investigate the trade-off between the input variables (morphological, suspension, and structural properties) and the final properties. Key variables like the type of furnish raw materials, including the fiber mixture, mechanical and enzymatic treatments, additives incorporation, and the type of industrial base tissue papers were taken under consideration. To achieve these relationships, we used different data-driven modeling approaches including multiple linear regression (MLR), artificial neural networks (ANN), and a 3D fiber-based simulator. The MLR and ANN models were built by data collected from an experimental design, and isotropic laboratory structures were prepared and tested for changes in structural and functional properties. Moreover, a 3D fiber-based simulator was used to investigate the influence of fibers on structural properties. These results indicated that the realistic predictions enabled us to link fiber and tissue structure characteristics. In conclusion, this work has revealed that this computational modeling approach can be used to model the effect of fiber pulps parameters with final end-use tissue properties, allowing to design innovative tissue products.

Computational Simulation Tools to Support the Tissue Paper Furnish Management: Case Studies for the Optimization of Micro/Nano Cellulose Fibers and Polymer-Based Additives.

Tissue paper production frequently combines two main types of raw materials: cellulose fibers from renewable sources and polymer-based additives. The development of premium products with improved properties and functionalities depends on the optimization of both. This work focused on the combination of innovative experimental and computational strategies to optimize furnish. The main goal was to improve the functional properties of the most suitable raw materials for tissue materials and develop new differentiating products with innovative features. The experimental plan included as inputs different fiber mixtures, micro/nano fibrillated cellulose, and biopolymer additives, and enzymatic and mechanical process operations. We present an innovative tissue paper simulator, the SimTissue, that we have developed, to establish the correlations between the tissue paper process inputs and the end-use paper properties. Case studies with industrial interest are presented in which the tissue simulator was used to design tissue paper materials with different fiber mixtures, fiber modification treatments, micro/nano fibrillated cellulose, and biopolymer formulations, and to estimate tissue softness, strength, and absorption properties. The SimTissue was able to predict and optimize a broader range of formulations containing micro/nanocellulose fibers, biopolymer additives, and treated-fiber mixtures, saving laboratory and industrial resources.

An Innovative Computational Strategy to Optimize Different Furnish Compositions of Tissue Materials Using Micro/Nanofibrillated Cellulose and Biopolymer as Additives.

The furnish management of tissue materials is fundamental to obtain maximum quality products with a minimum cost. The key fiber properties and fiber modification process steps have a significant influence on the structural and functional properties of tissue paper. In this work, two types of additives, a commercial biopolymer additive (CBA) that replaces the traditional cationic starch and micro/nanofibrillated cellulose (CMF), were investigated. Different formulations were prepared containing eucalyptus fibers and softwood fibers treated mechanically and enzymatically and both pulps with these two additives incorporated independently and simultaneously with drainage in the tissue process range. The use of these additives to reduce the percentage of softwood fibers on tissue furnish formulations was investigated. The results indicated that a maximum of tensile strength was obtained with a combination of both additives at the expense of softness and water absorbency. With a reduction of softwood fibers, the incorporation of additives increased the tensile strength and water absorbency with a slight decrease in HF softness compared with a typical industrial furnish. Additionally, a tissue computational simulator was also used to predict the influence of these additives on the final end-use properties. Both additives proved to be a suitable alternative to reduce softwood fibers in the production of tissue products, enhancing softness, strength and absorption properties.

Biopolymeric Delivery Systems for Cosmetic Applications Using Chlorella vulgaris Algae and Tea Tree Essential Oil.

Cosmetic products in which all the skincare compounds are biomolecules, biocompatible and biodegradable constitute a request of an educated consumer corresponding to a premium cosmetic segment. For this purpose, a cellulose-based delivery system was developed to retain biomolecules for dermic applications. The 3D matrix was built with microfibrillated cellulose, nanofibrillated cellulose and carboxymethylcellulose combined with a crosslinking agent, the alginate, to obtain a 3D matrix capable of retaining and releasing bioactive components of microalgae Chlorella vulgaris and tea tree essential oil. The porosity and pore dimensions and uniformity of this support matrix were optimized using 3D computational tools. The structures of the biopolymers were characterized using SEM, EDX, FTIR-ATR and DSC techniques. The essential oil and the microalgae components were successfully incorporated in a 3D stable matrix. The results indicate that the polymeric matrix retains and releases the essential oil biomolecules in a controlled way, when compared with tea tree essential oil, which is vaporized from 25 °C to 38 °C, without this 3D polymeric matrix. The microalgae and cellulose-based delivery system proved to be an interesting option for dermic and cosmetic applications because the exposure time of the therapeutic biomolecules was improved, and this factor consists of a competitive benefit for dermic systems.

Experimental 3D fibre data for tissue papers applications.

Tissue paper consumption has been growing for the past years, with a forecasted increase in demand for premium products. Premium tissue paper products are obtained with a balance among softness, strength, and absorption properties, optimized for each kind of tissue paper. These properties are influenced by the three-dimensional structure, made from the spatial distribution of cellulose fibres. To our knowledge, the efforts made to date to improve the softness, strength and absorption properties have overlooked the 3D structure. There is an absence of 3D experimental data in the literature for the simultaneous characterization of individual eucalyptus fibres and the paper structure made from these fibres. The 2D fibre morphology determination, including fibre length and fibre width, was obtained by an image analysis method for pulp fibre suspensions, using the MorFiⓇ equipment. The third fibre dimension, the fibre thickness morphology in the out-of-plane direction, was obtained using SEM images of non-pressed isotropic laboratory-made paper sheets. The effective fibre thickness morphology, consisting of the fibre wall and lumen, was measured in the paper structure, as this is precisely the key fibre parameter, influencing not only the structure-related properties, such as paper thickness, bulk, and porosity, but also the final end-use properties. The paper structures were produced using an ISO standard adapted method, for tissue paper structures, without pressing, with a basis weight range from 20 to 150 g/m2. These data are important, among other possible uses, for paper property optimization and simulation studies with 3D fibre based simulators.

Characterization data of pulp fibres performance in tissue papers applications.

The data presented in this article are related to the original research paper entitled "Comparative characterization of eucalyptus fibres and softwood fibres for tissue papers applications" available in Materials Letter: X Journal [1]. In this article, six eucalyptus hardwood pulps and six softwood pulps were characterized in terms of morphological, chemical and water-related (by drainability and water retention index) properties. In addition, using these pulps, unpressed laboratory isotropic handsheets were produced with a basis weight of approximately 20 g/m2, similarly to tissue papers. The key properties of tissue papers, namely structural properties, tensile index, absorption, and handfeel softness were analysed in these handsheets.