Bio-Based Waterborne PU for Durable Textile Coatings

Polyurethane (PU) coatings are often applied on high added value technical textiles. Key factor to success of PU coatings is its versatility and durability. Up to today most PU textile coatings are solvent-based or water-based. Recent advances are made in applying bio-based PU on textiles. Currently, polymers made from renewable raw materials are experiencing a renaissance, owing to the trend to reduce CO2 emissions, the switch to CO2-neutral renewable products and the depletion of fossil resources. However, the application of bio-based coatings on textiles is limited. The present paper discusses the potential of a bio-based anionic PU dispersion as an environment friendly alternative for petroleum-based PU in textile coating. Coatings were applied on textile via knife over roll. The chemical, thermal and mechanical properties of the bio-based PU coating were characterised via FT-IR, thermogravimetric analysis, differential scanning calorimetry and tensile test. The performance of the coating was studied by evaluating antimicrobial properties, fire retardancy, the resistance to hydrostatic pressure initially and after washing, QUV ageing and hydrolysis test. The developed bio-based PUD coating complied to the fire retardancy test ISO 15025 and exhibited excellent hydrostatic pressure, QUV ageing resistance, hydrolysis resistance, wash fastness at 40 °C.

PTHG2 Reduces Bone Loss in Ovariectomized Mice by Directing Bone Marrow Mesenchymal Stem Cell Fate

Teriparatide, also known as 1-34 parathyroid hormone (PTH (1-34)), is commonly used for the treatment of osteoporosis in postmenopausal women. But its therapeutic application is restricted by poor metabolic stability, low bioavailability, and rapid clearance. Herein, PTHG2, a glycosylated teriparatide derivative, is designed and synthesized to improve PTH stability and exert more potent antiosteoporosis effect. Surface plasmon resonance (SPR) analysis shows that PTHG2 combines to PTH 1 receptor. Additional acetylglucosamine covalent bonding in the first serine at the N terminal of PTH (1-34) improves stability and increases protein hydrolysis resistance. Intermittent administration of PTHG2 preserves bone quality in ovariectomy- (OVX-) induced osteoporosis mice model, along with increased osteoblastic differentiation and bone formation, and reduced marrow adipogenesis. In vitro, PTHG2 inhibits adipogenic differentiation and promotes osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs). For molecular mechanism, PTHG2 directs BMSCs fate through stimulating the cAMP-PKA signaling pathway. Blocking PKA abrogates the pro-osteogenic effect of PTHG2. In conclusion, our study reveals that PTHG2 can accelerate osteogenic differentiation of BMSCs and inhibit adipogenic differentiation of BMSCs and show a better protective effect than PTH (1-34) in the treatment of osteoporosis.

Synthesis of an urushiol derivative and its use for hydrolysis resistance in dentin adhesive

Synthesis of a natural plant monomer (urushiol) derivative and achieving a good performance in dentistry.

Modifying the thickness, pore size, and composition of diatom frustule in Pinnularia sp. with Al3+ ions

Diatoms are unicellular photosynthetic algae that produce a silica exoskeleton (frustule) which exposes a highly ordered nano to micro scale morphology. In recent years there has been a growing interest in modifying diatom frustules for technological applications. This is achieved by adding non-essential metals to the growth medium of diatoms which in turn modifies morphology, composition, and resulting properties of the frustule. Here, we investigate the frustule formation in diatom Pinnularia sp., including changes to overall morphology, silica thickness, and composition, in the presence of Al3+ ions at different concentrations. Our results show that in the presence of Al3+ the total silica uptake from the growth medium increases, although a decrease in the growth rate is observed. This leads to a higher inorganic content per diatom resulting in a decreased pore diameter and a thicker frustule as evidenced by electron microscopy. Furthermore, 27Al solid-state NMR, FIB-SEM, and EDS results confirm that Al3+ becomes incorporated into the frustule during the silicification process, thus, improving hydrolysis resistance. This approach may be extended to a broad range of elements and diatom species towards the scalable production of silica materials with tunable hierarchical morphology and chemical composition.

Synthesis, characterization and properties of biomass and carbon dioxide derived polyurethane reactive hot-melt adhesives

Polyurethane reactive hot-melt adhesives (PURHs) are frequently employed in industries; however, there is still a need to develop more sustainable and versatile methodologies to expand the functions and fabrication of these important materials. Renewable feedstock can give PURHs with new functions, and reduce environmental impact. This study focuses on synthesizing PURHs using polyols derived from biomass (plants) and greenhouse gas (CO2) resources. These PURHs were characterized by multiple techniques, including solid-state 13C nuclear magnetic resonance (NMR), a dynamic mechanical analysis (DMA), single-lap adhesive joints strength of stainless steel, and hydrolytic ageing. The PURH film based on biomass poly(tetramethylene ether) glycol (bio-PTMEG) exhibited better water vapor permeability, tensile strength, and adhesive joints properties than PURHs based on cashew nutshell liquid (CNSL) polyester diol and poly(propylene carbonate)-poly(propylene glycol) (PPC-PPG) copolymer diol. The polyols blend of bio-PTMEG with biomass and CO2 based polycarbonate diols respectively provided PURHs films excellent hydrolysis resistance and adhesive strength on single-lap adhesively bonded stainless steel specimens. The work herein demonstrates that various renewable polyols can be employed in a sustainable fashion to optimize the structures and properties of PURHs for important applications.

Polyhedral Oligomeric Silsesquioxane (POSS) Surface Grafting: A Novel Method to Enhance Polylactide Hydrolysis Resistance

This work considers the development of an easy and scalable approach to change the features of poly(l-lactide) (PLLA) films, which is based on the application of a surface treatment with an amino-functionalized polyhedral oligomeric silsesquioxane (POSS). Indeed, the developed approach is based on the potential reactivity of POSS amino group towards the polymer functionalities to produce an aminolysis reaction, which should promote the direct grafting of the silsesquioxane molecules on the polymer surface. Neat and treated films were studied by infrared spectroscopy and X-ray photoelectron spectroscopy, which proved the effectiveness of POSS grafting. Moreover, scanning electron microscopy measurements demonstrated the homogeneous distribution of Si on the film surface treated with the silsesquioxane. The influence of the film treatment on the surface wettability was evidenced by contact angle measurements. These findings demonstrated a relevant enhancement of the surface hydrophobicity, which increase turned out to depend on the conditions applied, as it increased by increasing the reaction temperature and the contact time. Finally, in order to evaluate the stability of neat and of the treated PLLA films the surface morphology of the samples treated with pH 7.4 buffer at 50 °C was studied.