Thermal and mechanical properties of chitosan nanocomposites with cellulose modified in ionic liquids

In this paper, ionic liquid treatment was applied to produce nanometric cellulose particles of two polymorphic forms. A complex characterization of nanofillers including wide-angle X-ray scattering, Fourier transform infrared spectroscopy, and particle size determination was performed. The evaluated ionic liquid treatment was effective in terms of nanocrystalline cellulose production, leaving chemical and supermolecular structure of the materials intact. However, nanocrystalline cellulose II was found to be more prone to ionic liquid hydrolysis leading to formation larger amount of small particles. Each nanocrystalline cellulose was subsequently mixed with a solution of chitosan, so that composite films containing 1, 3, and 5% mass/mass of nanometric filler were obtained. Reference samples of chitosan and chitosan with micrometric celluloses were also solvent casted. Thermal, mechanical, and morphological properties of films were tested and correlated with properties of filler used. The results of both, tensile tests and thermogravimetric analysis showed a significant discrepancy between composites filled with nanocrystalline cellulose I and nanocrystalline cellulose II

A comparative study of three-dimensional printing directions: The degradation and toxicological profile of a PLA/PHA blend

The use of biobased plastics is of great importance for many applications. Blending thermoplastic polylactide (PLA) with polyhydroxyalkanoate (PHA) enables the formulation of a more mechanically powerful material and this enables tailored biodegradation properties. In this study we demonstrate the 3D printing of a PLA/PHA blend as a potential candidate for biocompatible material applications. The filament for 3D printing consisted of PHA, which contains predominantly 3-hydroxybutyrate units and a small amount of 3-hydroxyvalerate units, as revealed by multistage mass spectrometry (ESI-MSn). This research found that the properties of 3D printed species before and during abiotic degradation are dependent on printing orientation. Furthermore, the 3D printed specimens exhibited good biocompatibility with HEK293 cells, indicating real promise as biological scaffolds for tissue engineering applications

Chitosan biocomposites with nanometric cellulose modified with dicarboxylic acid

Nanometryczną celulozę o dwóch odmianach polimorficznych (CNC I i CNC II), otrzymaną przy użyciu enzymów pochodzących od szczepu bakteryjnego Ochrobactrum anthropi, poddano modyfikacji kwasem pimelinowym. Badania szerokokątowej dyfraktometrii rentgenowskiej (WAXS) oraz spektroskopii w podczerwieni z transformacją Fouriera (FTIR) pozwoliły potwierdzić efektywność odpowiednio konwersji polimorficznej oraz modyfikacji chemicznej materiałów celulozowych. Wszystkie uzyskane napełniacze wykorzystano do wytworzenia kompozytów z chitozanem, które następnie poddano badaniom mechanicznym. Na podstawie zarejestrowanych krzywych rozciągania wyznaczono parametry cech wytrzymałościowych. Otrzymane kompozyty charakteryzowały się bardzo dobrymi właściwościami mechanicznymi. Zawartość 1% zmodyfikowanej CNC I okazała się być najefektywniejsza pod kątem zwiększania wartości modułu Younga oraz naprężenia maksymalnego przy zerwaniu. Zastosowanie modyfikacji chemicznej napełniaczy celulozowych za pomocą kwasu pimelinowego okazało się skuteczne wyłącznie dla materiałów o odmianie polimorficznej celulozy I.Nanometric celluloses of two polymorphic forms (CNC I and CNC II), obtained using the enzymes coming from Ochrobactrum anthropi bacteria, were chemically modified with pimelic acid. Wide angle X-ray scattering (WAXS) and infrared spectroscopy (FTIR) methods were used to confirm, respectively, supermolecular and chemical structures of cellulosic materials. After characterization nanometric celluloses, both modified and unmodified, were used as fillers for chitosan matrix. The obtained chitosan/nanometric cellulose composites were subjected to tensile tests. Based on the resultant tensile curves, the mechanical parameters were calculated. All the tested composites were characterized with good mechanical properties. However, in terms of Young’s modulus and tensile strength enhancement, addition of 1% of modified CNC I turned out to be optimal. Chemical modification of nanometric cellulose with pimelic acid was found to be effective only for materials with polymorphic form of cellulose I

Highly Insulative PEG-Grafted Cellulose Polyurethane Foams—From Synthesis to Application Properties

In this paper, native cellulose I was subjected to alkaline treatment. As a result, cellulose I was transformed to cellulose II and some nanometric particles were formed. Both polymorphic forms of cellulose were modified with poly(ethylene glycol) (PEG) and then used as fillers for polyurethane. Composites were prepared in a one-step process. Cellulosic fillers were characterized in terms of their chemical (Fourier transformation infrared spectroscopy) and supermolecular structure (X-ray diffraction), as well as their particle size. Investigation of composite polyurethane included measurements of density, characteristic processing times of foam formation, compression strength, dimensional stability, water absorption, and thermal conductivity. Much focus was put on the application aspect of the produced insulation polyurethane foams. It was shown that modification of cellulosic filler with poly(ethylene glycol) has a positive influence on formation of polyurethane composites—if modified filler was used, the values of compression strength and density increased, while water sorption and thermal conductivity decreased. Moreover, it was proven that the introduction of cellulosic fillers into the polyurethane matrix does not deteriorate the strength or thermal properties of the foams, and that composites with such fillers have good application potential

Multifunctional Polyurethane Composites with Coffee Grounds and Wood Sawdust

Currently, the fundamental activity that will allow for the development of an economy with closed circulation is the management of food waste and production waste for the preparation of biocomposites. The use of waste materials of natural origin allows for the creation of innovative composites with improved physicochemical and functional properties. The present investigation concerns the use of coffee grounds (2.5–20 wt.%) and oak sawdust (2.5–20 wt.%) as effective fillers of rigid polyurethane foam. Innovative composite materials, previously indebted in the literature, were subjected to the necessary analyses to determine the application abilities: processing times, free density, water absorption, dimensional stability, mechanical properties (compressive strength), thermal conductivity, morphology, and flame resistance. The results with respect to the mechanical tests turned out to be the key. Increasing the number of coffee additives has a positive effect on the compressive strength. The addition of this filler in the range of 5–15 wt.% increased the compressive strength of the composites, 136–139 kPa, compared to the reference sample, 127 kPa. The key parameter analysed was thermal conductivity. The results obtained were in range of the requirements, that is, 0.022–0.024 W/m·K for all used amounts of fillers 2.5–20 wt.%. This is extremely important since these materials are used for insulation purposes. The results of the burning-behaviour test have confirmed that the addition of renewable materials does not negatively affect the fire resistance of the received foams; the results were obtained analogously to those obtained from the reference sample without the addition of fillers. The height of the flame did not exceed 17 cm, while the flame decay time was 17 s for the reference sample and the composite with coffee grounds and 18 s for the composite with oak sawdust. In this work, the practical application of bioorganic waste as an innovative filler for the insulation of flooded polyurethane foam is described for the first time. The introduction of fillers of natural origin into the polymer matrix is a promising method to improve the physicochemical and functional properties of rigid polyurethane foams. Composites modified with coffee grounds and sawdust are interesting from a technological, ecological, and economic point of view, significantly increasing the range of use of foam in various industries

Functional MgO–Lignin Hybrids and Their Application as Fillers for Polypropylene Composites

Inorganic–organic hybrids are a group of materials that have recently become the subject of intense scientific research. They exhibit some of the specific properties of both highly durable inorganic materials (e.g., titanium dioxide, zinc) and organic products with divergent physicochemical traits (e.g., lignin, chitin). This combination results in improved physicochemical, thermal or mechanical properties. Hybrids with defined characteristics can be used as fillers for polymer composites. In this study, three types of filler with different MgO/lignin ratio were used as fillers for polypropylene (PP). The effectiveness of MgO-lignin binding was confirmed using Fourier transform infrared spectroscopy. The fillers were also tested in terms of thermal stability, dispersive-morphological properties as well as porous structure. Polymer composites containing 3 wt.% of each filler were subjected to wide angle X-ray diffraction tests, differential scanning calorimetry and microscopic studies to define their structure, morphology and thermal properties. Additionally, tensile tests of the composites were performed. It was established that the composition of the filler has a significant influence on the crystallization of polypropylene—either spherulites or transcrystalline layers were formed. The value of Young’s modulus and tensile strength remained unaffected by filler type. However, composites with hybrid fillers exhibited lower elongation at break than unfilled polypropylene

Thermal and Mechanical Properties of Silica–Lignin/Polylactide Composites Subjected to Biodegradation

In this paper, silica⁻lignin hybrid materials were used as fillers for a polylactide (PLA) matrix. In order to simulate biodegradation, PLA/hybrid filler composite films were kept in soil of neutral pH for six months. Differential scanning calorimetry (DSC) allowed analysis of nonisothermal crystallization behavior of composites, thermal analysis provided information about their thermal stability, and scanning electron microscopy (SEM) was applied to define morphology of films. The influence of biodegradation was also investigated in terms of changes in mechanical properties and color of samples. It was found that application of silica⁻lignin hybrids as fillers for PLA matrix may be interesting not only in terms of increasing thermal stability, but also controlled biodegradation. To the best knowledge of the authors, this is the first publication regarding biodegradation of PLA composites loaded with silica⁻lignin hybrid fillers

End-point determination of heterogeneous formulations using inline torque measurements for a high-shear wet granulation process

In this study, the torque profiles of heterogeneous granulation formulations with varying powder properties in terms of particle size, solubility, deformability, and wettability, were studied, and the feasibility of identifying the end-point of the granulation process for each formulation based on the torque profiles was evaluated. Dynamic median particle size (d50) and porosity were correlated to the torque measurements to understand the relationship between torque and granule properties, and to validate distinction between different granulation stages based on the torque profiles made in previous studies. Generally, the torque curves obtained from the different granulation runs in this experimental design could be categorized into two different types of torque profiles. The primary factor influencing the likelihood of producing each profile was the binder type used in the formulation. A lower viscosity, higher solubility binder resulted in a type 1 profile. Other contributing factors that affected the torque profiles include API type and impeller speed. Material properties such as the deformability and solubility of the blend formulation and the binder were identified as important factors affecting both granule growth and the type of torque profiles observed. By correlating dynamic granule properties with torque values, it was possible to determine the granulation end-point based on a pre-determined target median particle size (d50) range which corresponded to specific markers identified in the torque profiles. In type 1 torque profiles, the end-point markers corresponded to the plateau phase, whereas in type 2 torque profiles the markers were indicated by the inflection point where the slope gradient changes. Additionally, we proposed an alternative method of identification by using the first derivative of the torque values, which facilitates an easier identification of the system approaching the end-point. Overall, this study identified the effects of different variations in formulation parameters on torque profiles and granule properties and implemented an improved method of identification of granulation end-point that is not dependent on the different types of torque profiles observed