How to increse the viscosity of prepolymer using PO3G for spandex?5 answersTo increase the viscosity of a prepolymer for spandex using polyoxypropylene diol (PO3G), one can utilize isocyanate-terminated prepolymers formed by reacting excess isocyanate with an isocyanate-reactive component containing at least 10 equivalent percent of PO3G with specific molecular weight and unsaturation levels. Additionally, incorporating a viscosity controlling agent obtained by reacting organic diisocyanate with diol or diamine into the polymer for spandex can enhance viscosity without compromising material properties of the spandex thread. By following these methods, the viscosity of the prepolymer can be effectively increased for the production of spandex fibers.
How can viscometry be used to improve drug delivery?4 answersViscometry, specifically dynamic mechanical thermal analysis (DMTA), can be used to improve drug delivery by providing a comprehensive understanding of the viscoelastic properties of polymers. DMTA applies an oscillating stress or strain to a sample, allowing for the measurement of relaxation transitions and miscibility in pharmaceutical and biomedical systems. In-situ gelling delivery systems can also benefit from viscometry, as it enables the measurement of changes in rheology (gelation and dissolution) upon contact with physiological fluids. Additionally, predictive mathematical models of therapeutic release can be developed using viscometry, enhancing our understanding of drug formulations and improving control over drug release. Overall, viscometry provides valuable insights into the viscoelastic properties of polymers and can be used to optimize drug delivery systems.
How can biopolymers be modified for the synthesis of new biopolymer aerogels?5 answersBiopolymers can be modified for the synthesis of new biopolymer aerogels by compositing them with a polysiloxane network, which overcomes the drawbacks of hydrophilicity and difficulty in achieving homogeneous structures in nanoscale. Another approach is the deposition of protective hydrophobic and oleophobic polymer layers on hydrophilic biopolymer aerogels using cold plasma polymerization. The synthesis protocol of chitosan aerogels can be controlled to achieve desired microstructures by manipulating solvent-polymer and polymer-drying interactions. Computational approaches combining random closed packing of polydisperse spheres and Laguerre-Voronoi tessellation can be used to reconstruct or design the three-dimensional microstructure of nanoporous materials, such as κ-carrageenan aerogels. Urea-modified chitosan aerogels can be synthesized by triggering the irreversible gelation of an acidic chitosan solution through the thermal decomposition of urea, followed by drying using supercritical CO2 drying or ambient pressure drying methods.
Why do polysaccharides need any kind of modification for applications?3 answersPolysaccharides often require modification for various applications due to several reasons. Firstly, chemical modification of polysaccharides can enhance their biological activity, such as antioxidant, antitumor, immune regulation, antiviral, antibacterial, and anticoagulant functions in vitro. Secondly, modification of polysaccharides can alter their physicochemical properties, allowing for the design of tailor-made materials with improved characteristics. Additionally, structural modifications of polysaccharides can provide them with additional functional groups, expanding their potential applications. Moreover, modified polysaccharides have shown significant contributions to tissue engineering and drug delivery applications, making them valuable in the biomedical field. Lastly, chemical modifications of polysaccharides can further enhance their mechanical behavior, making them suitable for various industrial applications. Overall, the modification of polysaccharides allows for the optimization of their properties and expands their potential uses in different fields.
How does pbsa affect the elongational viscosity of pla?5 answersThe addition of poly(butylene succinate-co-adipate) (PBSA) to poly(lactic acid) (PLA) affects the elongational viscosity of PLA. The spray freeze-dried MMT (SFD-MMT) nanoparticles were used as reinforcement in PLA nanocomposites, and the elongational viscosity of the nanocomposites was evaluated. The addition of epoxycyclohexyl POSS (ePOSS) to PLA/PBSA blend significantly increased the storage modulus and complex viscosity, indicating higher melt elasticity and broader processing window. The addition of PBSA to PLA improved the melt flow characteristics of the blend, and the % elongation at break of the PLA/PBS blends was increased. The compatibility of the PLA/PBSA blend was influenced by the level of PBSA addition, and relatively low levels of PBSA addition improved the melt flow characteristics of the blend.
Does wetting ridge size increases with increase in oil viscosity?5 answersThe spreading behavior of water droplets immersed in oil is influenced by various factors. The size of wetting ridges, which are formed during spreading, can be affected by the viscosity of the oil. However, the relationship between wetting ridge size and oil viscosity is not explicitly mentioned in the abstracts provided.discusses the spreading of water droplets in oil and mentions that the spreading rate can be influenced by nanoscale topographic features. This suggests that the presence of such features may affect the size of wetting ridges, but the specific role of oil viscosity is not mentioned.focuses on the dewetting dynamics of heavy crude oil on solid substrates. It discusses the effect of temperature and pressure on the dewetting process, but does not directly address the relationship between wetting ridge size and oil viscosity.
Therefore, based on the information provided in the abstracts, it is not possible to determine whether wetting ridge size increases with an increase in oil viscosity.