Herein
is described the development of a large-scale manufacturing
process for molnupiravir, an orally dosed antiviral that was recently
demonstrated to be efficacious for the treatment of patients with
COVID-19. The yield, robustness, and efficiency of each of the five
steps were improved, ultimately culminating in a 1.6-fold improvement
in overall yield and a dramatic increase in the overall throughput
compared to the baseline process.
A comparison analysis has been undertaken to study the effect of different wood fillers on density and mechanical properties of two different types of commercial polyurethane (PUR) foams: low-density flexible foams and high-density rigid foams. The micro-fillers used were based on wood flour particles of size 70-250 microns (wood waste of furniture industry). The relationships between the filler size and content, density and various mechanical properties - compression test, compression force deflection test and modulus of elasticity have been studied. It was found that micro-fillers provide various effects depending on flexibility and density of PUR foams. For low-density flexible PUR foams, the density and mechanical properties increased for both types of fillers. However, for high-density rigid PUR foams these effects were just the opposite: the density and compression strengths decreased for both types of fillers. Explanation of the observed effects should take into consideration the chemical nature and physical structure of flexible and rigid PUR binders based on various types of polyol-isocyanate systems, as well as chemical and physical affiliation of cellulose based fillers with the matrices.
The main goals of the research were to develop the new types of inexpensive reinforced polyurethane (PUR) elastomers and to study the effect of different commercial fillers on the density and mechanical properties of the developed materials. Two types of inexpensive commercial fillers based on synthetic and natural polymers have been studied: expandable polystyrene beads (macrofillers) of size 0.254-2.54 mm, and wood flour and starch (microfillers) of size 0.212-0.425 mm. The quantitative relationships between the filler nature, size, content, density, and various mechanical properties have been developed.For both fillers it was found that PUR elastomers produced with less filler content (up to 5-10%) showed improved mechanical properties over the Downloaded from composites made with higher filler content (up to 10-30%). Regardless of the filler content, all filled elastomers demonstrated improvement of tensile properties over unfilled elastomers. The maximal improvement of tensile properties has been found as 10% for macrofillers, and 5% for microfillers. All developed materials are based on commercial formulations and mixing, metering, and pouring equipment. Thus, these materials are easy to commercialize. The developed reinforced cold-curing PUR composites have been recommended as inexpensive materials for structural, thermal insulation, and packaging applications, especially for in situ production.
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