The morphology of crystallisation of PHBV/PHBV copolymer blends

Langford, Alexandra; Chan, Clement Matthew; Pratt, Steven; Garvey, Christopher J.; Laycock, Bronwyn

doi:10.1016/j.eurpolymj.2018.12.022

Cited by 17 publications

(14 citation statements)

References 49 publications

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“…Figure 8 displays the storage modulus and tan δ curves from −20 °C to 100 °C. All blends exhibited a single peak in the tan δ curve, this being a relaxation attributed to the glass According to the literature, PHBV and PHBH both crystallized in the PHB lattice [63,66], but in different manners. PHBV is well-known to have an isomorphous co-crystallization behavior, depending on the major component of the copolymer.…”

Section: Dynamic Mechanical Analysismentioning

confidence: 72%

Development and Characterization of Fully Renewable and Biodegradable Polyhydroxyalkanoate Blends with Improved Thermoformability

et al. 2022

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Poly(3-hydroxybutyrate-co-3-valerate) (PHBV), being one of the most studied and commercially available polyhydroxyalkanoates (PHAs), presents an intrinsic brittleness and narrow processing window that currently hinders its use in several plastic applications. The aim of this study was to develop a biodegradable PHA-based blend by combining PHBV with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), another copolyester of the PHA family that shows a more ductile behavior. Blends of PHBV with 20% wt., 30% wt., and 40% wt. of PHBH were obtained by melt mixing, processed by cast extrusion in the form of films, and characterized in terms of their morphology, crystallization behavior, thermal stability, mechanical properties, and thermoformability. Full miscibility of both biopolymers was observed in the amorphous phase due to the presence of a single delta peak, ranging from 4.5 °C to 13.7 °C. Moreover, the incorporation of PHBH hindered the crystallization process of PHBV by decreasing the spherulite growth rate from 1.0 µm/min to 0.3 µm/min. However, for the entire composition range studied, the high brittleness of the resulting materials remained since the presence of PHBH did not prevent the PHBV crystalline phase from governing the mechanical behavior of the blend. Interestingly, the addition of PHBH greatly improved the thermoformability by widening the processing window of PHBV by 7 s, as a result of the increase in the melt strength of the blends even for the lowest PHBH content.

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Section: Dynamic Mechanical Analysismentioning

confidence: 72%

Development and Characterization of Fully Renewable and Biodegradable Polyhydroxyalkanoate Blends with Improved Thermoformability

et al. 2022

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“…10 Polyhydroxyalkanoates (PHAs), a family of fermentation derived biodegradable polyesters, have received extensive attention. 14,15 There are more than 150 PHA species, such as poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), 16 poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] (P34HB), 17 and so forth. In our previous work, we have found that a high content of PHBV (PHBV content ≥ 30 wt.%) could significantly improve the heat resistance of the PLA fibers.…”

mentioning

confidence: 99%

Toward heat resistant polylactide blend fibers via incorporation of low poly[(R)‐3‐hydroxybutyrate‐co‐4‐hydroxybutyrate] content

Shi

Huang

Li³

et al. 2022

J of Applied Polymer Sci

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Blending high content of polyhydroxyalkanoates (PHAs ≥ 30 wt.%) with polylactide (PLA) provides an effective strategy to significantly improve heat resistance of PLA fibers. However, it has proven challenging to maintain good spinnability of the PLA/PHAs blends with the high content of PHAs. In this study, a series of poly(L‐lactide) (PLLA)/poly[(R)‐3‐hydroxybutyrate‐co‐4‐hydroxybutyrate] (P34HB) blend fibers with low P34HB content (≤ 8 wt.%) is successfully fabricated with excellent spinnability. The incorporation of P34HB contributes to a substantially improved heat resistance of the PLLA/P34HB blend fibers, as evidenced by a notable reduction in boiling water shrinkage from ca. 80% to 9%. This exceptionally improved heat resistance is closely related to substantial increase in crystallinity of PLLA in the blend fibers. Specifically, the addition of low P34HB content remarkably enhances chain mobility of PLLA chains, as such reduces crystallization half‐times (t1/2) and accelerates crystallization of PLLA. In fact, the amorphous P34HB phase favors crystal growth of PLLA phase rather than heterogeneous nucleation inferred previously. These results provide a facile and effective method to produce PLLA/P34HB blend fibers with enhanced heat resistance and sound spinnability.

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“…It was previously observed that PHBV could form either banded or nonbanded spherulites depending on the different crystallization temperatures and PHBV blends. [ 40 ] Previous study on PHB showed that the final spherulite morphology is controlled by the competition of the crystallization rate and the diffusion rate of melt molecules. [ 30 ] In another study on PHBV, HV content was found to influence the direction of PHBV lamellar twist.…”

Section: Resultsmentioning

confidence: 99%

Comparison of nanocrystalline cellulose dispersion versus surface nucleation in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) crystallization

Haham

Shen²,

Billington

et al. 2020

SPE Polymers

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Nanocrystalline cellulose (NCC), which is a known crystal nucleating agent, is utilized to improve poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) thermal properties. Since NCC aggregation in PHBV negatively affects composite properties and processability, NCC crystal nucleation effectiveness was examined at low concentrations (<1%) under isothermal and nonisothermal conditions. NCC was dispersed in PHBV solutions using a solvent exchange method and then cast into films. We found that NCC was an effective nucleating agent in amounts as low as 0.25%, resulting in an increase in PHBV crystallization rate by more than 50%. However, increasing to 1% NCC resulted in aggregation in PHBV, with the NCC becoming less effective compared to lower NCC concentrations. In an attempt to improve NCC dispersion, we added cellulose acetate (CA) or stearic acid (SA) to the casting solution, anticipating that CA or SA would preferentially adsorb on the NCC. With such pretreatment, dispersion was indeed improved but NCC became less effective as a PHBV nucleating agent. This work shows the advantage of using low NCC concentrations (<0.5%) for promoting PHBV crystallization, but the lack of improved nucleation upon addition of CA and SA supports the importance of NCC surface accessibility.

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The morphology of crystallisation of PHBV/PHBV copolymer blends

Cited by 17 publications

References 49 publications

Development and Characterization of Fully Renewable and Biodegradable Polyhydroxyalkanoate Blends with Improved Thermoformability

Development and Characterization of Fully Renewable and Biodegradable Polyhydroxyalkanoate Blends with Improved Thermoformability

Toward heat resistant polylactide blend fibers via incorporation of low poly[(R)‐3‐hydroxybutyrate‐co‐4‐hydroxybutyrate] content

Comparison of nanocrystalline cellulose dispersion versus surface nucleation in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) crystallization

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