RESUMO
This paper studies the structure-property-processing relationship of polyphthalamide (PPA) PPA/polyamide 4,10 (PA410) blends, via co-relating their thermal-mechanical properties with their morphology, crystallization, and viscoelastic properties. When compared to neat PPA, the blends show improved processability with a lower processing temperature (20 °C lower than neat PPA) along with a higher modulus/strength and heat deflection temperature (HDT). The maximum tensile modulus is that of the 25PPA/75PA410 blend, ~3 GPa, 25% higher than neat PPA (~2.4 GPa). 25PPA/75PA410 also exhibits the highest HDT (136 °C) among all the blends, being 11% more than PPA (122 °C). The increase in the thermo-mechanical properties of the blends is explained by the partial miscibility between the two polymers. The blends improve the processing performance of PPA and broaden its applicability.
RESUMO
A full factorial design with four factors (the ratio of polyphthalamide (PPA) and polyamide 4,10 (PA410) in the polymer matrix, content percent of biocarbon (BioC), the temperature at which it was pyrolyzed and the presence of a chain extender (CE)), each factor with two levels (high and low), was carried out to optimize the mechanical properties of the resulting composites. After applying a linear model, changes in tensile strength, elongation at break and impact energy were not statistically significant within the considered material space, while the ones in the flexural modulus, the tensile modulus, density and heat deflection temperature (HDT) were. The two most influential factors were the content of BioC and its pyrolysis temperature, followed by the content of PPA. The affinity of PPA with a high-temperature biocarbon and the affinity of PA410 with a lower-temperature biocarbon, appear to explain the mechanical properties of the resulting composites. The study also revealed that the addition of CE hindered the mechanical properties. By maximizing the flexural modulus, tensile modulus and HDT, while minimizing the density, the optimal composite predicted is an 80 [PPA:PA410 (25:75)] wt% polymer composite, with 20 wt% of a BioC, pyrolyzed at a calculated 823 °C.
RESUMO
Reducing greenhouse gas emissions (GHG) in vehicles requires the use of lighter-weight materials. One possible strategy is using biomass-derived carbons (biocarbon), which have a lower density compared to traditional mineral based fillers. In this study, novel composites reinforced with 20 and 30 wt% of a biocarbon produced at high temperature (950 °C) were melt compounded with polyphthalamide (PPA), followed by injection molding, and compared to talc-filled composites. Mechanical tests were performed with ASTM standard samples for tensile, flexural and impact properties, alongside thermal, spectroscopic and morphological characterizations. Surface area and elemental composition of the biocarbon and talc particles were also determined. The biocarbon and talc composites had matching mechanical properties in most of the tests (3.7 GPa for the Young's modulus of the 20 wt% talc-filled composite versus 3.7 GPa for both 20 wt% biocarbon-filled composites), with all the properties surpassing those of the unfilled, neat PPA (Young's modulus of 2.4 GPa), and the biocarbon-filled composites have a lower density than the talc-filled ones (1.277 g cm-3 for the 20 wt% talc-filled composite versus 1.176 g cm-3 for both 20 wt% biocarbon-filled composites). The main influencing factors for the better performance of the biocarbon-PPA composites were found to be the similarity of particle size between the talc and the biocarbon.
