An analysis of targeted properties of materials used for preservation and storage of heritage collections

The aim of this study was to stress the importance of investigating the prop- erties of preservation enclosure materials in order to identify the ones that are able to protect their contents more efficiently. Since not all information on materials is covered by international standards and technical specifica- tions, nine paper-based materials used for making preservation enclosures (file folders, passepartouts, boxes etc.) were investigated. A selective analysis of the materials' properties was carried out to determine smoothness, water absorptiveness, water wettability, water vapor permeability, tensile strength, folding endurance, bursting strength, puncture strength, as well as loss of bursting strength caused by dry heat and 100% RH. Results obtained from measuring smoothness, water absorptiveness, water wettability and water vapor transmission rate indicate that a material outside of ISO 16245:2009 grammage requirements for making file covers can exhibit more desirable properties than the one that meets multiple standards for storage and preservation. Additionally, results showed that bursting strength of enclosure materials was significantly affected by both extreme microclimate condi- tions. However, 100% RH had affected bursting strength of the investigated materials more than dry heat. The presented procedure proved to be a useful indicator of materials’ properties within the context of heritage collections preservation and storage.

Cassava-Starch-Based Films Incorporated with Buriti (Mauritia flexuosa L.) Oil: A New Active and Bioactive Material for Food Packaging Applications

The objective of this study was to develop and characterize cassava-starch-based films incorporated with buriti (Mauritia flexuosa L.) oil and emulsifier (Tween 20). An experimental factorial design 22 with three central points was used to develop the films, by varying the concentrations of buriti oil (0.15 to 0.45% w/v) and emulsifier (0.02 to 0.04% w/v). Film thickness and weight increased with increasing buriti oil concentration. The water vapor permeability of the films ranged from 0.22 to 0.366 g mm h−1 m−2 kPa−1. The tensile strength values varied from 4.21 to 6.95 MPa, the elasticity modulus varied from 538.53 to 722.78 MPa, and elongation to rupture varied from 1.13 to 1.66%. The film color was characterized as yellowish, dark, and intense (higher oil content); and clear and a low-intensity color (lower oil content). The films presented a total carotenoid content ranging from 3.63 to 29.73 μg β-carotene/g, which may have resulted in their antioxidant potential against DPPH• (1,1-diphenyl-2-picryl-hydrazyl) radical (from 74.28 to 87.74%). The central formulation of the experimental design (buriti oil 0.30% and emulsifier 0.03%) presented a good performance and can be applied as packaging for foods with a lower water content and that demand protection against oxidation.

Hybrid films from plant and bacterial nanocellulose: mechanical and barrier properties

The accumulation of petroleum polymers compromises biodiversity and causes environmental problems. Nanocellulose enhances biodegradability and can improve the physical-mechanical performance of materials. The objective was to produce and characterize hybrid films composed of bacterial cellulose (BC) and plant nanocellulose from Eucalyptus (Euc) or Pinus (Pin). Films were produced by the casting method using filmogenic suspensions with different cellulose nanofibrils (CNFs) proportions from both the sources (0, 25, 50, 75 and 100 %). CNFs suspensions were characterized by transmission electron microscopy. The morphology of the films was analyzed using scanning electron microscopy. In addition, the transparency, contact angle, wettability, oil and water vapor barrier and mechanical properties were also evaluated. The contact angles were smaller for films with BC and the wettability was greater when comparing BC with plant CNFs (0.10 ° s − 1 {\text{s}^{-1}} for 75 % Euc/25 % BC and 0.20 ° s − 1 {\text{s}^{-1}} for 25 % Euc/75 % BC). The water vapor permeability (WVP) of the 100 % BC films and the 25 % Euc/75 % BC composition were the highest among the studied compositions. Tensile strength, Young’s modulus and puncture strength decreased considerably with the addition of BC in the films. More studies regarding pre-treatments to purify BC are needed to improve the mechanical properties of the films.

ВИЗНАЧЕННЯ ГІГІЄНІЧНИХ ВЛАСТИВОСТЕЙ ВКЛАДНИХ ІНДИВІДУАЛЬНИХ ЗАСОБІВ З ВСТАВКАМИ РОСЛИННОЇ СИРОВИНИ У ВЗУТТЯ

Purpose: To conduct experimental studies of embedded hygienic installed insoles with tableted plant inserts in footwearMethodology. The properties of embedded hygienic insoles have been studied for vapor permeability and moisture content according to the methods of GOST 22900-78. The solid inserts were ground and extracted with distilled water for a week to obtain aqueous extracts for microbiological studies. Determination of antimicrobial activity was performed using a culture of S.aureus ATCC 25923 in microtiter 96-well plates in liquid nutrient medium NB spectrophotometrically by optical density (Hipo MPP-96, Biosan, λ = 620 nm, control medium – by the location of a non-sterile sample with (30 × 30 mm) on the surface of sterile NA medium.Findings. To improve the hygienic characteristics of the inner space of the shoe, the research presents embedded hygienic products with solid inserts in the form of tablets from the plant raw materials of medicinal thyme and sage. The technological characteristics of tableted inserts from vegetable raw materials are given. The results of vapor permeability and moisture content in the studied samples are obtained, which correspond to the normative values according to GOST 940-81 and are safe for human feet.Originality. Determination of indicators of vapor permeability and moisture content of embedded hygienic installed insoles with tableted plant inserts and establishing their compliance with regulatory requirements. Determined the regularities of inhibitory effect of aqueous extracts of thyme on the growth of biomass of gram-negative bacteria in planktonic culture.Practical value. Another advantage of custom-made shoes is the ability to consider the customer's preferences regarding shoe care products during the operation. At the same time, an important task is to ensure the hygiene of the inner space of the shoe through the use of insoles containing elements obtained from medicinal plant materials.

Nanofiber/hydrogel core–shell scaffolds with three-dimensional multilayer patterned structure for accelerating diabetic wound healing

Impaired angiogenesis is one of the predominant reasons for non-healing diabetic wounds. Herein, a nanofiber/hydrogel core–shell scaffold with three-dimensional (3D) multilayer patterned structure (3D-PT-P/GM) was introduced for promoting diabetic wound healing with improved angiogenesis. The results showed that the 3D-PT-P/GM scaffolds possessed multilayered structure with interlayer spacing of about 15–80 μm, and the hexagonal micropatterned structures were uniformly distributed on the surface of each layer. The nanofibers in the scaffold exhibited distinct core–shell structures with Gelatin methacryloyl (GelMA) hydrogel as the shell and Poly (d, l-lactic acid) (PDLLA) as the core. The results showed that the porosity, water retention time and water vapor permeability of the 3D-PT-P/GM scaffolds increased to 1.6 times, 21 times, and 1.9 times than that of the two-dimensional (2D) PDLLA nanofibrous scaffolds, respectively. The in vitro studies showed that the 3D-PT-P/GM scaffolds could significantly promote cell adhesion, proliferation, infiltration and migration throughout the scaffolds, and the expression of cellular communication protein-related genes, as well as angiogenesis-related genes in the same group, was remarkably upregulated. The in vivo results further demonstrated that the 3D-PT-P/GM scaffolds could not only effectively absorb exudate and provide a moist environment for the wound sites, but also significantly promote the formation of a 3D network of capillaries. As a result, the healing of diabetic wounds was accelerated with enhanced angiogenesis, granulation tissue formation, and collagen deposition. These results indicate that nanofiber/hydrogel core–shell scaffolds with 3D multilayer patterned structures could provide a new strategy for facilitating chronic wound healing. Graphical Abstract

Comparison of Numerical HMT Codes to Simulate MBV Test of Hemp-Earth Composites

Bio-based and earth materials are growingly used for the building envelopes because of their numerous benefits such as slight environmental impact, great hygrothermal performances, effective regulation of the perceived indoor air quality and human comfort. In such materials, the phenomenon of mass transfer is complex and has a great impact on the performance of building envelope. Therefore, it is important to identify and understand the hygrothermal phenomena to be able to simulate accurately the envelope behavior. Nevertheless, the classical models that depict hygric transport within building materials seem not accurate enough for bio-based materials as they are simplified on several points of view. The correlation that exists between water content and relative humidity is mostly simplified and is modeled by a single curve, the hygric storage capacity is often overstated and the hysteresis is neglected. This paper deals with numerical study of hygric transfer within hemp-earth building material by using WUFI® Pro 6.5, a commercial software, and TMC code developed at the LGCGM (Moissette and Bart, 2009) . This code was validated regarding EN 15026 standard (Moissette and Bart, 2009) and has evolved over the years by integrating the hysteresis phenomena (Aït-Oumeziane et al., 2015). Thus, a significant enhancement of the numerical simulations on desorption phase was shown. This study investigates the simulation of MBV test performed on a hemp-earth material for which only the adsorption curve is known as input. Missing parameters (water vapor permeability and desorption curve) are fitted considering the first cycle of MBV test with TMC code. Then, MBV test is simulated with WUFI® Pro 6.5 and TMC code without and with hysteresis. The results highlight the need to include hysteresis to accurately simulate dynamic hygric phenomena, and show that it is possible to find missing parameters by fitting dynamic solicitations.

Evaluation of a Marine Dredged Sediment as Raw Material Compared to Volcanic Scoria for the Development of Lime-Pozzolan Eco-Binders

In the context of global warming, the built environment offers relevant opportunities to reduce GHG emissions that underlie climate change. In particular, this can be achieved with the development of low-embodied energy building materials such as bio-based concretes. Hemp concrete has been the subject of many investigations in the field of non-load bearing infill walls in France since the early 1990s. In addition to hygrothermal performances, the use of crop by-products definitely helps to limit the carbon footprint. Hemp concretes are often produced by mixing the plant aggregates with lime-based binders. The latter have many benefits among which the water vapor permeability. However, CO2 emissions due to the decarbonation of limestone for the production of lime largely contribute to the overall environmental balance of these materials. The use of natural pozzolans (volcanic scoria) combined with hydrated lime goes back to the Greco-Roman period and reduces carbon emissions. Nonetheless, it does not necessarily meet the issue related to the depletion of granular natural resources. Hence, this study deals with the design of a new low-carbon binder based on marine dredged sediment seen as an alternative strategic granular resource that can be considered renewable. The sediment comes from the Port of Dunkirk in the North of France and is mainly composed of silt and quartz sand. It was finely ground and compared to a lowly reactive basaltic pozzolan. Lime-pozzolan pastes were prepared and stored in a moist environment under room (20°C) and high temperature (50°C). The hardening kinetics of pastes was followed through mineralogical studies (TGA, XRD) and compressive strength development. The results showed that the hardening of pastes including the marine sediment was suitable in the case of samples stored at 50°C and make it possible to use such a binder for precast bio-based concretes.

Morphology, Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect

Carboxymethyl rice starch films were prepared from carboxymethyl rice starch (CMSr) treated with sodium hydroxide (NaOH) at 10–50% w/v. The objective of this research was to determine the effect of NaOH concentrations on morphology, mechanical properties, and water barrier properties of the CMSr films. The degree of substitution (DS) and morphology of native rice starch and CMSr powders were examined. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to investigate the chemical structure, crystallinity, and thermal properties of the CMSr films. As the NaOH concentrations increased, the DS of CMSr powders increased, which affected the morphology of CMSr powders; a polyhedral shape of the native rice starch was deformed. In addition, the increase in NaOH concentrations of the synthesis of CMSr resulted in an increase in water solubility, elongation at break, and water vapor permeability (WVP) of CMSr films. On the other hand, the water contact angle, melting temperature, and the tensile strength of the CMSr films decreased with increasing NaOH concentrations. However, the tensile strength of the CMSr films was relatively low. Therefore, such a property needs to be improved and the application of the developed films should be investigated in the future work.

Multilayer nonwoven lining materials made of wool and cotton for clothing and footwear

Five types of multilayer nonwovens for clothing and footwear parts were obtained by the adhesive bonding method. The thickest middle layer of the material consists of evenly laid coarse camel or sheep fibers or of reconstituted cotton fibers from flaps, the upper and lower layers consist of knitwear, and polymer adhesive is located between the layers. The layers are bonded by thermal pressing at a temperature of 150 ± 5°C for 2.0 ± 0.2 min. The microstructure and morphology of fibers, polymer adhesive, and multilayer nonwoven fabric were investigated by FT-IR spectroscopy, SEM, and X-ray phase analysis. The chemical interaction between wool fibers and polymer adhesive, the geometric dimensions and shape of the fibers, the structure and morphology of the cross section of the layers of the material, and the change in the degree of crystallinity of the material have been established. The investigated coarse and thick fibers of camel and sheep wool are more suitable for the production of nonwoven textile material. In the process of thermal exposure, the molten polymer diffuses into the structure of the nonwoven layer and knitted fabric. The diffusion and excellent adhesion of the molten polymer to the fibers ensures the solidity and strength of the composite. The developed design provides high strength of the material as a whole and adhesive strength between layers, high heat-retaining properties, and the use of a mesh adhesive film provides sufficient air and vapor permeability.

A Model for Assessment of Heat and Moisture Transfer Hollow a Hemp Concerte Wall Using Finite Element Method

The energy performance of buildings represents a major challenge in terms of sustainable development. The buildings and buildings construction sectors combined are responsible for over one-third of global final energy consumption and nearly 40% of total direct and indirect CO2 emissions. In order to reduce the energy consumption of buildings and their harmful impact on the environment, special attention has been paid in recent years to the use of bio-based materials. In the present paper, a model of heat and moisture transfer hollow hemp concrete wall is proposed using finite element method. The energy and mass balances are expressed using measurable transfer drivers as temperature water content and vapor pressure and coefficients related explicitly to the macroscopic properties of material as thermal conductivity, specific heat, and water vapor permeability. The proposed model is implemented in MATLAB code and validated through experimental measurements.