Poly granules

Fig. 3. Operating pressure and mass of solids entering and leaving conveying pipeline for unstable flow of poly granules through 21.7 m long and 60 mm ID stainless steel pipeline.

In the case of poly(vinyl chloride) plastics, the FWA is mixed dry with the PVC powder before processing or dissolved in the plasticising agent (see Vinyl polymers). Polystyrene, acrylonitrile—butadiene—styrene (ABS), and polyolefin granulates are powdered with FWA prior to extmsion (2,78) (see... 

Ghdants are needed to faciUtate the flow of granulation from the hopper. Lubricants ensure the release of the compressed mass from the punch surfaces and the release/ejection of the tablet from the die. Combinations of siUcas, com starch, talc (qv), magnesium stearate, and high molecular weight poly(ethylene glycols) are used. Most lubricants are hydrophobic and may slow down disintegration and dmg dissolution. 

In a typical process, 100 parts of poly(vinyl acetate) are added to a mixture of 200 parts acetic acid and 70 parts water, which has been warmed to about 70°C, and stirred to complete solution. Sixty parts of 40% formalin and 4 parts sulphuric acid (catalyst) are added and reaction is carried out for 24 hours at 1Q°C. Water is added to the mixture with rapid agitation to precipitate the granules, which are then washed free from acid and dried. 

At the bottom of the tower, the high molar mass poly(styrene) is extruded, granulated, and cooled prior to packaging. 

Iyer et al. [50] investigated the effects of roto-granulation on the performance of hydroxypropyl methylcellulose (HPMC), gelatin, and poly(-vinylpyrrolidone) (Povidone, PVP). In this process, all three binders produced similar results. However, HPMC was preferred due to prolonged drug release profiles, smaller particle size, and better content uniformity. 

A new pathway was recently engineered in vitro employing purified His6-tag-ged PhaCl and PhaC2 from P. aeruginosa plus a commercially available acyl-CoA synthetase allowing in vitro de novo PHA granules and in vitro synthesis of poly(3HD) from 3-hydroxydecanoate [74]. 

Poly(3-hydroxybutyrate), poly(3HB), or PHB is a bacterially produced polyester which appears in bacterial cells as discrete granules. The capability of synthesizing poly(3HB) is widespread in prokaryotes [1-3]. This capability is neither a taxon-related property nor an ecophysiological peculiarity. It is largely inde-... 

Poly(HASCL) depolymerases are able to bind to poly(3HB)-granules. This ability is specific because poly(3HB) depolymerases do not bind to chitin or to (crystalline) cellulose [56,57]. The poly(3HB)-binding ability is lost in truncated proteins which lack the C-terminal domain of about 60 amino acids, and these modified enzymes do not hydrolyze poly(3HB). However, the catalytic domain is unaffected since the activity with water-soluble oligomers of 3-hy-droxybutyrate or with artificial water-soluble substrates such as p-nitrophenyl-esters is unaffected [55, 56, 58, 59]. Obviously, the C-terminal domain of poly(3HB) depolymerases is responsible and sufficient for poly(3HB)-binding [poly(3HB)-binding domain]. These results are in agreement ... 

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