Blends with Poly 3-hydroxybutyrate

PCL was also blended with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymers on a small two-roll mill for 5 min at 140 °C (12% HV) or 128 °C (20% HV). The blends were injection moulded to produce tensile test samples. Samples were prepared in the presence of 1 wt % hydroxyapatite as a crystal nucleating agent and to reduce sample preparation time. For both copolymers, the addition of PCL (10 wt %) reduced the initial modulus and tensile strength (Table 12). Samples containing 90 wt % of PCL exhibited properties very similar to those of PCL and the effects were attributed to phase separation from the blends brought about by PHBV crystallisation at temperatures exceeding T for PCL. That is, the samples show immiscibility. Even blends containing 10 wt % PCL samples aimealed in aqueous media or in an oven showed the presence of crystalline PCL. 

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). 

The adverse environments experienced during high temperature processing are exemplified by studies on PS blends with PIB [La Mantia and NociUa, 1987] and with PE [Komova et al., 1991 1992], of PE/PP blends [La Mantia et al., 1985], and of poly(hydroxy acids) blends with poly(hydroxybutyrates) [Gogolewski et al.,... 

Oigan SJ (1994) Phase separation in blends of poly(hydroxybutyrate) with poly(hydroxybutyrate-co-hydiox5rvalerate) variation with blend components. Polymer 35 86-92 Oigan SJ, Barham PJ (1993) Phase separation in a blend of poly(hydroxybutyrate) with poly(hydroxybutyrate-co-hydroxyvalerate). Polymer 34 459-467 Ouyang SP, Liu Q, Fang L, Chen GQ (2007) Construction of a p/w-operon-defined knockout mutants of Pseudcmonas putida KT2442 and their applications in poly(hydroxyalkanoate) production. Macromol Biosd 7 227—233... 

Kim MN, Lee A, Lee K, Chin I, Yoon J. BiodegradabUity of poly(3-hydroxybutyrate) blended with poly(ethylene-co-vinyl acetate. Fur Polym J 1999 35 (6) 1153-1158. 

For blends of poly(butylene succinate) with poly(hydroxybutyrate-co-hydroxyvalerate or poly(hydroxybutyrate) compatibilized in the presence of radical initiator, see Ma et al. (2012a). 

Gilmore, D. F., Lotti, N. and Lenz, R. W. et al. (1992) Biodegradability of blends of poly(hydroxybutyrate-co-hydroxyvalerate) with ester-substituted celluloses, in Biodegradable Polymers and Plastics (eds M. Vert et al.). Royal Society of Chemistry, Cambridge, pp. 251-4. 

The determination of the experimental variables for apphcation of this approach is based on analysis of FTIR data on the blends and is covered in the references noted above. The application of the association model to determine or predict the phase behavior of interacting polymer systems include poly(2,6-dialkyl-4-vinyl phenol) blends with poly(n-alkyl methacrylates) and ethylene-vinyl acetate copolymers [217], poly(4-vinyl phenol)/poly(hydroxybutyrate) blends [218] and poly(4-vinyl phenol) in ternary blends with PEMA and PMMA [219] as weU as a number of examples in [92]. The determination of the equihbrium constants Ka and Kb) from FTIR data has been reported for ethylene-methacryhc add copolymers with polyethers [118] and ethylene-methacrylic add copolymers with poly(2-vinyl pyridine) [220]. 

D.F. Gilmore, N. Lotti, R.W. Lenz, R.C. Fuller and M. Scandola, "Biodegradability of blends of poly(hydroxybutyrate-co- hydroxyvalerate) with ester-substituted celluloses", in "Biodegradable Polymers and Plastics", M. Vert, J. Feijen, A. Albertsson, G. Scott and E. Chiellini eds.. Royal Society of Chemistry, London, 251-254,1992. 

Fig. 11.4 Plot of spherulite growth rates of poly(pivalolactone) as a function of composition in blends with poly(vinylidene fluoride) (circles), pivalolactones and poly(3-hydroxybutyrate) in cellulose acetate butyrate (squares), at indicated crystallization temperatures. (Data from (2) and (5))...

Polymer Blends. The miscibility of poly(ethylene oxide) with a number of other polymers has been studied, eg, with poly (methyl methacrylate) (18—23), poly(vinyl acetate) (24—27), polyvinylpyrroHdinone (28), nylon (29), poly(vinyl alcohol) (30), phenoxy resins (31), cellulose (32), cellulose ethers (33), poly(vinyl chloride) (34), poly(lactic acid) (35), poly(hydroxybutyrate) (36), poly(acryhc acid) (37), polypropylene (38), and polyethylene (39). 

The blending of different polymers is a frequently used technique in industrial polymer production to optimize the material s properties. The biodegradable polymer poly(3-hydroxybutyrate) (PHB) [45, 46], for example, which can be produced by bacteria from renewable resources, has the disadvantage of being stiff and brittle. The mechanical properties of PHB, however, can be readily enhanced by blending with another biopolymer, poly(lactic acid) (PLA) [47]. In order to prepare the optimum blend, it must be noted that the miscibility of different polymers depends on their concentration, the temperature, and their structural characteristics [48]. 

Kikkawa, Y Suzuki, T Kanesato, M. Doi, Y and Abe, H. Effect of phase structure on enzymatic degradation in poly(L-lactide)/atactic poly(3-hydroxybutyrate) blends with different miscibility. Biomacromole. 2009,10(4), 1013-1018. 

However, in addition to their thermoplasticity, representatives of PHAs have optical activity, increase induction period of oxidation, exhibit the piezoelectric effect and, what is most important, they are characterized as being biodegradable and biocompatible. At the same time, the PHAs have disadvantages (high cost, brittleness), which can be partially or completely compensated by using composite materials based on blends with other polymers, with dispersed fillers or plasticizers. Taking into account all the above, we have suggested to create a mixed polymer composite based on poly-3-hydroxybutyrate (PHB) and polyisobutylene (PIB). 

Innocentini-Mei, L. H., Bartoli, J. R Baltieri, R. C., Mechanical and thermal properties of poly(3-hydroxybutyrate) blends with starch and starch derivatives. Macromolecular Symnosia. 1, 77-88 (2003), DOl 10.1002/masy.200350708. 

Multilayer co-extrusion is another technique used in the preparation of starch/ synthetic sheets or films [164, 263-266], in which TPS is laminated with appropriate biodegradable polymers to improve the mechanical, water-resistance and gas-barrier properties of final products. These products have shown potential for applications such as food packaging and disposable product manufacture. Three-layer co-extrusion is most often practiced, in which a co-extrusion line consists of two single-screw extruders (one for the inner starch layer and the other for the outer polymer layers) a feedblock a coat-hanger-type sheet die and a three-roll calendering system [164]. Biodegradable polyesters such as PCL [164, 264], PLA [164, 263], and polyesteramide, PBSA and poly(hydroxybutyrate-co-valerate) [164] are often used for the outer layers. These new blends and composites are extending the utilization of starch-based materials into new value-added products. 

Satoh, H., Yoshie, N., Inoue, Y. Hydrolytic degradation of blends of poly (3-hydroxybutyrate) with poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Polymer 35(2), 286-290 (1994)... 

Kumagai, Y., and Doi, Y., 1992, Enzymic degradation and morphologies of binaiy blends of microbial poly(3-hydroxybutyrate) with poly(e-cainolactone), poly(l,4- butylene adipate) and poly(vinyl acetate). Polym. Degrad. Stab. 36 241-248. 

Blends were prepared with cellulose or silk as soon as a common solvent was available [63, 69-71]. Recently, ionic liquids were used. The solvent l-ethyl-3-methyl-imidazolium acetate completely dissolves raw crustacean shells allowing to recover high purity chitin powder or films and fibres by direct spinning [72]. Films of poly(e-caprolactone) (PCL) blends with a-chitin and chitosan were produced. They are completely biodegradable and the crystallinity of PCL is suppressed in the blends due to hydrogen bond interaction between PCL and polysaccharides [73]. Blends were also realized with poly (3-hydroxybutyric acid) (PHB) and chitin or chitosan. They show faster biodegradation than the pure-state component polymers [74,75]. 

Ikejima, T., Yagi, K. and Inoue, Y. (1999) Thermal properties and crystallization behaviour of poly(3-hydroxybutyric acid) in blends with chitin and chitosan. Macrrmwlectdar Chemistry and Physics, 200, 413 21. 

Ohkoshi, I., Abe, H. and Doi, Y. (2000) MiscibiUty and soUd-state structures for blends of poly[(S)-lactide] with atactic poly[(R,S)-3-hydroxybutyrate]. Polymer, 41, 5985-5992. 

PHA blends are usually prepared via the solvent-casting and meltcompounding methods. Blends of PHA have attracted considerable attention as the resulting blends potentially have extraordinary properties. Various compounds could be blended with PHA to obtain the desired characteristics for instance, poly(3-hydroxybutyrate)... 

Koyama H, Doi Y (1996) Misdbitity, thermal properties, and enzymatic degradability of binary blends of poly[(J )-3-hydroxybutyric acid] with poly(8-caprolactone-co-lactide). Macromolecules 29 5843-5851... 

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