Adsorption of Polystyrene from Theta Condition on Cellulose and Silica Studied by Quartz Crystal Microbalance.

Adsorption of hydrophobic polymers from a nonpolar solvent medium is an underutilized tool for modification of surfaces, especially of soft matter. Adsorption of polystyrene (PS) from a theta solvent (50/50 vol % toluene/heptane) on ultrathin model films of cellulose was studied with a quartz crystal microbalance with dissipation monitoring (QCM-D), using three different PS grades with monodisperse molecular weights (s). Comparison of cellulose to silica as an adsorbent was presented.

Assessment of the Alga as a Source for Cellulose Nanocrystals.

Nanocellulose is isolated from cellulosic fibers and exhibits many properties that macroscale cellulose lacks. Cellulose nanocrystals (CNCs) are a subcategory of nanocellulose made of stiff, rodlike, and highly crystalline nanoparticles. Algae of the order Cladophorales are the source of the longest cellulosic nanocrystals, but manufacturing these CNCs is not well-studied.

Understanding Nanocellulose-Water Interactions: Turning a Detriment into an Asset.

Modern technology has enabled the isolation of nanocellulose from plant-based fibers, and the current trend focuses on utilizing nanocellulose in a broad range of sustainable materials applications. Water is generally seen as a detrimental component when in contact with nanocellulose-based materials, just like it is harmful for traditional cellulosic materials such as paper or cardboard. However, water is an integral component in plants, and many applications of nanocellulose already accept the presence of water or make use of it.

Chitin-Active Lytic Polysaccharide Monooxygenases Are Rare in Species.

Cellulomonas flavigena is a saprotrophic bacterium that encodes, within its genome, four predicted lytic polysaccharide monooxygenases (LPMOs) from Auxiliary Activity family 10 (AA10). We showed previously that three of these cleave the plant polysaccharide cellulose by oxidation at carbon-1 (J. Li, L.

Controlled sulfation of mixed-linkage glucan by Response Surface Methodology for the development of biologically applicable polysaccharides.

Endogenous and exogenous sulfated polysaccharides exhibit potent biological activities, including inhibiting blood coagulation and protein interactions. Controlled chemical sulfation of alternative polysaccharides holds promise to overcome limited availability and heterogeneity of naturally sulfated polysaccharides. Here, we established reaction parameters for the controlled sulfation of the abundant cereal polysaccharide, mixed-linkage β(1,3)/β(1,4)-glucan (MLG), using Box-Behnken Design of Experiments (BBD) and Response Surface Methodology (RSM).

On the properties of nanosilicate-based filled dental adhesives: Synthesis, characterization, and optimized formulation.

Objective: In this study, we incorporated hybrid nanoparticles (poly (acrylic acid)-grafted nanoclay/nanosilica, respectively, with platelet and spherical morphologies, abbreviated as PAA-g-NC-Sil) in different concentrations (0, 0.2, 0.5, 1, 2 and 5 wt%) to an experimental dentin bonding system and investigated the physical properties of the filled adhesive and its shear bond strength (μ-SBS) to dentin.

Four cellulose-active lytic polysaccharide monooxygenases from Cellulomonas species.

Background: The discovery of lytic polysaccharide monooxygenases (LPMOs) has fundamentally changed our understanding of microbial lignocellulose degradation. Cellulomonas bacteria have a rich history of study due to their ability to degrade recalcitrant cellulose, yet little is known about the predicted LPMOs that they encode from Auxiliary Activity Family 10 (AA10).

Results: Here, we present the comprehensive biochemical characterization of three AA10 LPMOs from Cellulomonas flavigena (CflaLPMO10A, CflaLPMO10B, and CflaLPMO10C) and one LPMO from Cellulomonas fimi (CfiLPMO10).

Dual modified nanosilica particles as reinforcing fillers for dental adhesives: Synthesis, characterization, and properties.

A facile procedure has been devised to develop a novel dentin bonding system containing poly (acrylic acid)-grafted-silanized fumed silica particles as reinforcing filler, with high stability of nanoparticle dispersion and enhanced bond strength and mechanical properties. In the first step, the silanization of fumed silica nanoparticles was performed in the following conditions: (i) ethanol-water solution with a pH of 5 and (ii) cyclohexane with a pH of 9 using trimethoxysilylpropyl methacrylate (γ-MPS) as a reactive silane coupling agent. FTIR and TGA analyses confirmed the presence of silane in the resultant structure and enhanced dispersion stability of modified particles was proved by a separation analyzer and also zeta potential analyses.

Poly (methacrylic acid) modified spherical and platelet hybrid nanoparticles as reinforcing fillers for dentin bonding systems: Synthesis and properties.

Objective: In this study the mechanical and adhesion properties of an experimental methacrylate based dentin bonding system containing a combination of spherical and layered platelet nanoparticles were investigated. The nanoparticles were first modified through surface graft polymerization of methacrylic acid in order to make the particles surface compatible with the bonding matrix resin.

Materials And Methods: Graft free radical polymerization in aqueous media was performed to attach Poly (methacrylic acid) (PMA) chains onto the surface of Na-MMT nanoclay (Cloisite® Na+) and silica nanoparticles (Aerosil® 200).

Structure-properties relationships in dental adhesives: Effect of initiator, matrix monomer structure, and nano-filler incorporation.

Objectives: This is a confirmatory study to evaluate the effect of photoinitiator type and concentration, matrix monomer chemical structure, and nanoparticle incorporation on the physical and mechanical properties of an experimental dentin bonding agent.

Materials And Methods: Different concentrations of camphorquinone-amine (CQ-A) system, butanedione (BD), and phenylpropanedione (PPD), as photoinitiator, BTDMA, as a comonomer containing carboxylic acid groups, and silica nanoparticles as reinforcing inorganic filler were incorporated into a methacrylate base experimental dental adhesive. The effect of these ingredients, as independent variables, on the shrinkage kinetics, flexural strength and modulus, and microshear bond strength of the adhesives were then investigated.

Physical characterization of unfilled and nanofilled dental resins: Static versus dynamic mechanical properties.

Objective: The aim of this study was to evaluate the mechanical properties of dental resins and dental nanocomposites by means of 3-point bending, 4-point bending and piston-on-three ball biaxial static tests and also to investigate their dynamic mechanical properties. The obtained results from the static 3-point bending test also were compared with the corresponding mode in DMTA.

Methods: The hydrophilic surface of the inorganic OX-50 particles was treated with γ-MPS and the resulting silanized OX-50 was characterized using FTIR and TGA.

Synthesis and in vitro characterization of a preactivated thiomer via polymerization reaction.

The objective of this study was to synthesize 6-(2-acryloylamino-ethyldisulfanyl)-nicotinic acid (ACENA) for subsequent copolymerization with acrylic acid (AA) as a new method for synthesis of preactivated thiomers. Copolymerization reactions of ACENA and AA with different molar ratios were performed and the molecular weight (M(w)) values of the resulting copolymers were calculated and reported from 3046 to 3271 Da. The disulfide bond content values in the polymer chain were determined from 400 to 544 μmol disulfide bond per gram polymer.

A novel dentin bonding system containing poly(methacrylic acid) grafted nanoclay: synthesis, characterization and properties.

Objectives: Developing a novel dentin bonding system containing poly(methacrylic acid)-grafted-nanoclay (PMAA-g-nanoclay) as reinforcing filler, with high stability of nanoparticle dispersion and improved bond strength and mechanical properties were the main objectives of this study.

Materials And Methods: Poly(methacrylic acid) (PMAA) was grafted onto the pristine sodium montmorrillonite (Na-MMT) nanoclay surface and characterized using FTIR, TGA, and X-ray diffraction (XRD). The PMAA-g-nanoclay was incorporated into an experimental dentin bonding system as filler in different concentrations and stability of nanoclay dispersion in the dilute adhesive, morphology of nanoclay layers in the photocured adhesive matrix, shear bond strength to caries-free extracted human premolar teeth, and mode of failure were studied.

Poly(acrylic acid) grafted montmorillonite as novel fillers for dental adhesives: synthesis, characterization and properties of the adhesive.

Objective: This work investigates the graft polymerization of acrylic acid onto nanoclay platelets to be utilized as reinforcing fillers in an experimental dental adhesive. Physical and mechanical properties of the adhesive and its shear bond strength to dentin are studied. The effect of the modification on the stability of the nanoparticle dispersion in the dilute adhesive is also investigated.

PMMA-grafted nanoclay as novel filler for dental adhesives.

Objective: The aim of this study was to investigate the benefits of incorporation of poly(methyl methacrylate)-grafted-nanoclay on the bond strength of an experimental one-bottle dentin bonding system. The effect of the modification on the stability of the nanoparticle dispersion in the dilute adhesive was also studied.

Materials And Methods: Poly(methyl methacrylate) was grafted onto the pristine Na-MMT nanoclay (Cloisite Na(+)) through the free radical polymerization of methyl methacrylate in an aqueous media in the presence of ammonium persulfate as initiator.