Poly hydroxyvalerate

Another soft aliphatic polyester that may be used in manufacturing the pol5mer blends is poly(hydroxybutyTate-hydroxyvalerate) copolymer (PHBV), which is manufactured using a microbial-induced fermentation. One such PHBV copolyester is manufactured by Monsanto Company and has a glass transition temperature of about 0°C and a melting point of about 170°C. 

Bacteria that can produce 3-hydroxyhexanoate based polymers are summarized in Table 4.2. 

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A co-polymer of P(3-HB) and poly(hydroxyvalerate) P(3-HV) is also found in microorganisms and performs the same function. This polyester forms the basis for a good strong but flexible plastic for containers such as toiletries, and is produced by ICI under the name BIOPOL . Microorganisms must be able to degrade both P(3-HB) and BIOPOL since they themselves use them to store energy. 

The MALDI spectrum of a pure polymer resembles a comb and the spacing between the comb s teeth equals the mass, Tr, of the repeat unit. This quantity is often diagnostic and it suggests an almost trivial use of MALDI, namely spectral identification of polymers. The reason is that if one computes LIr values for common polymers, most values are different, the number of superpositions being very low. For instance, the most common polyethers are poly (ethylene oxide), poly (propylene oxide), poly(tetrahydrofuran), and poly(2,5-dimethyl phenylene oxide), and some common aliphatic polyesters are poly(caprolactone),poly(lactic acid), poly (hydroxy-butyrate), and poly(hydroxyvalerate). No superposition occurs (Pr values are 44, 58, 72, 120, 114, 72, 86, and 100 Da, respectively). 

Poly(hydroxybutyrate), Poly(hydroxyvalerate), and Their Copolymers... 

Pearce, R. P. and Marchessault, R. H. Melting and CrystalUzation in Bacterial Poly(/ -hydroxyvalerate), PHV, and Blends with Poly(/3-hydroxybutyrate-co-hydroxyvalerate). Macromolecules. 27 3869-3874 (1994). 

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