Effect of nucleating agents on the crystallization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)

Abstract

The effect of nucleating agents on the crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was studied. A differential scanning calorimeter was used to monitor the energy of the crystallization process from the melt and melting behavior. During the crystallization process from the melt, nucleating agent led to an increase in crystallization temperature (T c ) of PHBV compared with that for plain PHBV (without nucleating agent). The melting temperature of PHBV changed little with addition of nucleating agent. However, the areas of two melting peaks changed considerably with added nucleating agent. During isothermal crystallization, dependence of the relative degree of crystallization on time was described by the Avrami equation. The addition of nucleat-ing agent caused an increase in the overall crystallization rate of PHBV, but did not influence the mechanism of nucleation and growth of the PHB crystals. The equilibrium melting temperature of PHBV was determined as 187°C. Analysis of kinetic data according to nucleation theories showed that the increase in crystallization rate of PHBV in the composite is due to the decrease in surface energy of the extremity surface.

Bioplastics from waste glycerol derived from biodiesel industry

“…This has led to studies on the nucleation behavior of P(3HB) homopolymer and the P(3HB-co-3HV) copolymers. 37,38 The nucleation density of pure P(3HB) is often too low for efficient initiation of crystallization. The limited nuclei formed in pure P(3HB) leads to low numbers of spherulites so that the size of each P(3HB) spherulite is relatively large.…”

“…39,40 P(3HB-co-3HV) also exhibited a slow crystallization behavior, which resulted in the films made from the copolymer with high 3HV mole fraction to remain tacky after cooling from the melting temperature. 41 A number of external nucleating agents, such as orotic acid, 42 boron nitride, 38 a-cyclodextrin, 43 talc, 38 saccharin and phthalimide, 44 have been studied to increase the crystallization rate of PHA polymers. These nucleating agents are also capable of increasing the number of spherulites.…”

The Effect of Polystyrene on the Crystallization of Poly(3-hydroxybutyrate)

“…The general trend towards a decrease in crystallinity with increasing cooling rates can be explained by the decrease in the available time to develop the crystals. At cooling rates lower than 10°C/min the crystallinity of the blends was equal or even higher that the crystallinity neat PHB, which may be caused by the fact that PS particles acted as heterogeneities and promoted the crystallinity 3,12 . However, as the cooling rate increased, the crystallinity of the blend decreases to values lower than those for the neat resin.…”

Morphology and thermal properties of biodegradable poly(hydroxybutyrate-co-hydroxyvalerate)/tungsten disulphide inorganic nanotube nanocomposites

“…7, incorporating 1.0 wt.% INT WS 2 effectively increased the peak crystallization temperature to a value compa rable to that of BN, and greater than all other NAs. BN is currently estimated to be more expensive than INT WS 2 and, like talc, is not a nanoparticle filler, also possibly leading to deficient mechanical reinforcement qualities that are observed with other nano sized filler materials [20]. Also noteworthy, MWCNT filled PHBHV [23] showed an appreciable DT but the nanotubes were chemically modified to incorporate carboxyl group tails on the nanotube sur face to reduce surface tension for better dispersion within the PHBV matrix.…”