Effect of heat cycling on melting and crystallization of PHB/TiO2 compounds

Jaques, Nichollas Guimarães; Silva, Ingridy Dayane dos Santos; Neto, Manoel da Cruz Barbosa; Ries, Andreas; Canedo, Eduardo L.; Wellen, Renate Maria Ramos

doi:10.1590/0104-1428.12416

Cited by 13 publications

(6 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…P(3HB) and PHBV3% both displayed one unique and narrow melting peak centered at around T m1 = 176.5 °C for P(3HB) and T m1 = 174.5 °C for PHBV3% and crystallization temperatures of around 82 °C ( T c = 81.9 °C for P(3HB) and T c = 82.8 °C for PHBV3%). These temperatures meet the results reported in the literature. − The thermal behavior of PHBV18% was quite different from the ones observed for the two commercial PHAs, with, however, little difference between the two levels of purification. For PHBV18%-P1 and PHBV18%-P2, crystallization occurred at a higher temperature than for P(3HB) and PHBV3%, i.e., T c = 96.7 °C for PHBV18%-P1 and T c = 97.4 °C for PHBV18%-P2.…”

Section: Results and Discussionsupporting

confidence: 85%

Effect of the Molecular Structure of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-3HV)) Produced from Mixed Bacterial Cultures on Its Crystallization and Mechanical Properties

et al. 2020

View full text Add to dashboard Cite

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P-(3HB-3HV)) copolymer's properties depend on (i) the molar fraction of comonomers, (ii) the overall molar mass, and (ii) the chemical compositional distribution. This work aims at providing a better understanding of the effect of the P(3HB-3HV) molecular structure, produced from mixed cultures and waste feedstock, on copolymer crystallization and tensile properties. Conventional biopolymer characterization methods (differential scanning calorimetry, X-ray diffraction, and polarized optical microscopy) were coupled to both classical one-dimensional ( 1 H and 13 C) and advanced two-dimensional (diffusion-ordered spectroscopy (DOSY) and 1 H/ 13 C heteronuclear single quantum coherence (HSQC)) nuclear magnetic resonance (NMR) spectroscopy techniques. The obtained results evidenced that (i) a high-quality copolymer could be achieved, even from a waste feedstock; (ii) increasing the 3HV content displayed a positive impact on P(3HB-3HV) mechanical properties only if good interactions between 3HB and 3HV moieties were established; and (iii) the purification process eliminated short-length 3HV-rich chains and promoted homogeneous co-crystallization. Such optimized microstructures enabled the maximal stress and strain at break to be increased by +41.2 and +100%, respectively.

show abstract

Section: Results and Discussionsupporting

confidence: 85%

Effect of the Molecular Structure of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-3HV)) Produced from Mixed Bacterial Cultures on Its Crystallization and Mechanical Properties

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Indeed, PHB exhibits good mechanical and oxygen barrier properties. Moreover, it is stable under normal usage conditions but undergoes rapid biodegradation under composting conditions [ 14 ]. Nevertheless, PHB is susceptible to thermal degradation, has a narrow processing window, and shows severe post-process embrittlement, which reduces the applicability of this biopolymer [ 3 , 10 , 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of Chitin Nanocrystals on the Crystallinity and Mechanical Properties of Poly(hydroxybutyrate) Biopolymer

et al. 2022

View full text Add to dashboard Cite

This study focuses on the use of pilot-scale produced polyhydroxy butyrate (PHB) biopolymer and chitin nanocrystals (ChNCs) in two different concentrated (1 and 5 wt.%) nanocomposites. The nanocomposites were compounded using a twin-screw extruder and calendered into sheets. The crystallization was studied using polarized optical microscopy and differential scanning calorimetry, the thermal properties were studied using thermogravimetric analysis, the viscosity was studied using a shear rheometer, the mechanical properties were studied using conventional tensile testing, and the morphology of the prepared material was studied using optical microscopy and scanning electron microscopy. The results showed that the addition of ChNCs significantly affected the crystallization of PHB, resulting in slower crystallization, lower overall crystallinity, and smaller crystal size. Furthermore, the addition of ChNCs resulted in increased viscosity in the final formulations. The calendering process resulted in slightly aligned sheets and the nanocomposites with 5 wt.% ChNCs evaluated along the machine direction showed the highest mechanical properties, the strength increased from 24 to 33 MPa, while the transversal direction with lower initial strength at 14 MPa was improved to 21 MPa.

show abstract

“…Figure 15 a,b shows the relative crystallinity and crystallization rate of pure PA6 and blends, respectively. The relative crystallinity curves of pure PA6 and its blends had a sigmoidal shape, suggesting phase transformation [ 60 , 61 ]. Compared with other formulations, the crystallization process started at higher temperatures for pure PA6 and PA6/ABS (10%) blend.…”

Section: Resultsmentioning

confidence: 99%

Influence of Small Amounts of ABS and ABS-MA on PA6 Properties: Evaluation of Torque Rheometry, Mechanical, Thermomechanical, Thermal, Morphological, and Water Absorption Kinetics Characteristics

et al. 2022

View full text Add to dashboard Cite

In this work, polyamide 6 (PA6) properties were tailored and improved using a maleic anhydride-grafted acrylonitrile-butadiene-styrene terpolymer (ABS-MA). The PA6/ABS-MA blends were prepared using a co-rotational twin-screw extruder. Subsequently, the extruded pellets were injection-molded. Blends were characterized by torque rheometry, the Molau test, Fourier transform infrared spectroscopy (FTIR), impact strength, tensile strength, Heat Deflection Temperature (HDT), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Contact Angle, Scanning Electron Microscopy (SEM), and water absorption experiments. The most significant balance of properties, within the analyzed content range (5, 7.5, and 10 wt.%), was obtained for the PA6/ABS-MA (10%) blend, indicating that even low concentrations of ABS-MA can improve the properties of PA6. Significant increases in impact strength and elongation at break have been achieved compared with PA6. The elastic modulus, tensile strength, HDT, and thermal stability properties of the PA6/ABS-MA blends remained at high levels, indicating that maleic anhydride interacted with amine end-groups of PA6. Torque rheometry, the Molau test, and SEM analysis suggested interactions in the PA6/ABS-MA system, confirming the high properties obtained. Additionally, there was a decrease in water absorption and the diffusion coefficient of the PA6/ABS-MA blends, corroborating the contact angle analysis.

show abstract

Effect of heat cycling on melting and crystallization of PHB/TiO2 compounds

Cited by 13 publications

References 41 publications

Effect of the Molecular Structure of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-3HV)) Produced from Mixed Bacterial Cultures on Its Crystallization and Mechanical Properties

Effect of the Molecular Structure of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-3HV)) Produced from Mixed Bacterial Cultures on Its Crystallization and Mechanical Properties

Influence of Chitin Nanocrystals on the Crystallinity and Mechanical Properties of Poly(hydroxybutyrate) Biopolymer

Influence of Small Amounts of ABS and ABS-MA on PA6 Properties: Evaluation of Torque Rheometry, Mechanical, Thermomechanical, Thermal, Morphological, and Water Absorption Kinetics Characteristics

Contact Info

Product

Resources

About