Poly PHBV

PHB poly(3-hydroxybutanoic acid) PHBV poly(3-hydroxybutanoic acid-co-3-hydroxyvaleric acid), ref. 105. CCAPA poly(e-caprolactone) FB100, ref. 456. 

Researchers at the Hawaii Natural Energy Institute, University of Hawaii, have also developed a novel, two-step process that converts organic waste materials such as food scraps into poly(3-hydroxybutyrate) or PHBV (26). Approximately 60% of the organic material is converted into PHAs, and the remaining 40% can be converted into fertilizers (27). The first step... 

Composites of granular starch with poly(hydroxy alkanoates) (PHAs) have been extensively studied. PHAs are produced as energy storage polymers by a wide range of microorganisms. Poly(hydroxy butyrate-co-valerate) (PHBV) copolymers have been commercialized. These copolymers are completely biodegradable, but currently are several times more costly than commodity polymers such as PE and PS. Because of its low cost, starch is an attractive filler for these materials. 

Avella, M. Matuscelli, E. Raimo, M. Properties of blends and composites based on poly(3-hydroxy)butyrate (PHB) and poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) copolymers. J. Mater. Sci. 2000, 35, 523-545. 

Poly(3-hydroxybutyrate) (PHB) and its copolymer poly(3-hydroxybutyrate-co-3-bydroxyvalerate) (PHBV) are ratber resistant towards moisture and tbeir cbemical hydrolysis at neutral pH and ambient temperature proceeds slowly through random chain scission [78,79]. The rate of chemical hydrolysis decreases with increasing crystallinity [80]. There is no agreed explanation to how the copolymer composition affects the hydrolysis rate. It has been suggested that it is the crystalhnity, rather than the composition that affects the hydrolysis rate. On the other hand, PHBVs of the same crystalhnity, but different compositions (45-71 mol% HV), showed decreasing hydrolysis rates with increasing HV-content [81]. 

PHBV Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PVC Poly(vinyl chloride)... 

Higher molecular weight PHB and its copolymers with poly(3-hydroxy-valerate) (PHV) can be synthesized from racemic P-butyrolactone and P Valerolactone, using an oligomeric alumoxane catalyst. These polyesters, with only partial stereoregularity, are less susceptible to enzymatic degradation than the bacterial ones. Polyhydroxy-butyrate-valerate (PHBV) is produced by Monsanto as Biopol . 

Biopol (purchased from Zeneca Ltd. of ICI by Monsanto Co.) Poly-hydroxy butyrate valerate (PHBV) prepared from glucose by fermentation. The resins are used for extrusion coating, bottles, cutlery, toothbrushes, etc. 

Poly(3-hydroxy butyric acid) and poly(3-hydroxyl valeric acid) copolymers are formed by the fermentation of glucose with the aid of Alcaligenes eutrophus species. As a result of using copolymers, PHBV is synthesised via polymerisation (Figure 5.3). 

Poly(3-hydroxybutyrate- o-3-hydroxyvalerate) (PHBV) is a soft, malleable and thermosoftening biodegradable polymer material. It can be easily converted into films, which are applicable for packaging, carry bags, disposable bottles and so on. The hydrophilic backbone chain of the polymer, which contains atoms of oxygen in the polymer chain, accelerates the degradation of bacteria and pathogens. 

Muhamad, I. L Joon, L. K. Noor, M. A. M. Comparing the degradation of poly-P-(hydroxybutyrate), poly-P-(hydroxybutyrate-co-valerate) (PHBV) and PHBV/Cellu-lose triacetate blend. Malaysian Polym. J. 2006,1, 39 6. 

The nomenclature of PHAs and their classification are still in the process of evolving, because new structures are continuing to be discovered. The main biopolymer in the PHA family is a homopolymer polyhydroxybutyrate (PHB). The most conunon copolymer is poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), whose chemical structure is presented in Figure 9.4. However, there are others, such as poly(hydroxybulyrate-co-hydroxyhexanoate) (PHBHx), poly(hydroxybutyrate-co-hydroxyoctanoate) (PHBO) and poly(ltydroxybulyrate-co-hydroxyoctadecanoate) (PHBOd), for example. 

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