Thermal Stability and Flammability Behavior of Poly(3-hydroxybutyrate) (PHB) Based Composites

Abstract

A series of samples based on poly(3-hydroxybutyrate) (PHB) containing five different additives were prepared and their thermal stability and flammability were discussed. The samples first underwent flammability screening by using Pyrolysis Combustion Flow Calorimeter (PCFC) analyses. Then, four samples were selected for further investigations. PHB composites containing sepiolite (Sep.) inorganic nanofiller, and also organic ammonium polyphosphate (APP) were examined for flammability and thermal behavior using PCFC, thermogravimetric analysis (TGA), flame test, and Differential Scanning Calorimetry (DSC) analyses. Moreover, burning behavior of samples were captured on a digital camera to give a deeper sense of their flammability character for comparison. The results revealed a significant improvement of flammability and thermal stability of composites, particularly in the presence of sepiolite with respect to the value obtained for unfilled PHB. Regarding TGA results, the char residue yield was increased to ca. 20.0 wt.% in the presence of sepiolite, while 0.0 wt.% was observed for PHB. PCFC measurements uncovered higher performance of PHB-Sep. sample as signaled by 40% reduction in the peak of heat release rate with respect to PHB. According to observations, PHB-Sep. sample showed non-dripping behavior with high capacity of charring in the presence of Sep. in a vertical flame test.

Enhanced polyhydroxybutyrate (PHB) production by newly isolated rare actinomycetes Rhodococcus sp. strain BSRT1-1 using response surface methodology

“…Thermal analyses showed that the extracted PHB existed as a thermally stable semi-crystalline polymer 55 , the T m and T g of extracted PHB were 171.8 and 4.03 °C, respectively. Similar T m and T g have been previously reported in PHB 63 – 65 . The maximum thermal decomposition observed was at 288 °C by FIIR and is related with the ester cleavage of PHB by b-elimination reaction 67 .…”

“…The maximum thermal decomposition observed was at 288 °C by FIIR and is related with the ester cleavage of PHB by b-elimination reaction 67 . Many researchers have been reported similar TGA results of PHB 55,[63][64][65][66] . All these results confirmed that the polymer produced by R. pyridinivorans BSRT1-1 is PHB homopolymer, and the properties of extracted PHB were similar to the commercial PHB 68 .…”

Blends of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) with Fruit Pulp Biowaste Derived Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate-co-3-Hydroxyhexanoate) for Organic Recycling Food Packaging

“…The blends with different contents in P(3HB- co -3HV- co -3HHx) presented the maximum of melting in the range of 169–174 °C with ∆H m values of 74 and 68 J/g for the film samples with 10 and 25 wt% of terpolymer, respectively, whereas the films with 50 wt% of terpolymer showed a value of 43 J/g. As it can also be observed in the DSC curves, the neat P(3HB- co -3HV- co -3HHx) presented a very complex melting behavior, exhibiting the highest endothermic peaks at 111 °C, ascribed to the lowest crystalline density fractions of the terpolymer [ 59 , 60 ], and at 173 °C, for the most thermodynamically stable 3HB-rich fractions [ 61 ]; and having a whole ∆H m value of 33 J/g. Thus, in the blend samples, a drop in T m and ∆H m was generally observed when P(3HB- co -3HV- co -3HHx) was incorporated into PHBV.…”

“…The diffractograms, included in Figure 4 , revealed two main peaks located at 13.6 and 17.0° 2θ, corresponding to the (020) and (110) lattice planes of the orthorhombic unit cell of PHB [ 67 ]. These intense peaks were followed by three other minor reflections centered at approximately 22.6, 25.8, and 26.9° 2θ, which originate from (111), (121), and (040) lattice planes [ 61 , 68 ]. The diffraction peaks found here agree well with those reported in the literature, where the crystal lattice of PHBV with 3HV contents below 30 mol% corresponds to the unit cell of PHB [ 69 ].…”

Flame Retardancy of Bio-Based Polyurethanes: Opportunities and Challenges

“…In the synthesis of conventional PUs, polyols and isocyanates are usually derived from petrochemical sources. Over recent decades, growing concerns about global warming resulting from human activity, depletion of fossil resources, and fluctuating oil price has prompted debate among researchers exploring bio-based resources to replace starting chemicals with green, sustainable, and renewable sources [ 10 , 11 , 12 , 13 , 14 ]. Thus, biopolymers derived from biological and renewable sources have attracted the attention of researchers due to their sustainability, abundant availability, and eco-friendliness [ 4 ].…”