The influence of the drying process time on the final properties of recycled glass fiber reinforced polyamide 6

The direct long-fiber reinforced thermoplastic (D-LFT) process offers a streamlined material processing technique and decreases the degradation of the material. To ensure product consistency and process optimization, it is imperative to understand how the process sequence affects degradation and thermal properties of the material during the D-LFT process. This study investigates variation in molecular weight and thermal properties of the glass fiber reinforced polyamide 6 (PA6) composites throughout the D-LFT process. Viscosity number (VN) measurements, thermogravimetric analyses (TGA), and differential scanning calorimetry (DSC) analyses were performed on samples taken from different locations along the D-LFT process. It was found that VN, which is a measure of molecular weight of the PA6 base resin, decreased throughout the processes. In contrast, TGA results suggested that apparent activation energy for decomposition increased during consecutive process stages. Nonisothermal DSC results showed that there were no significant changes to the degree of crystallization; however, isothermal DSC results indicated that later stages of the process showed a decrease in crystallization half-time, and the largest changes were observed in areas after the two extrusion portions of the process. POLYM. ENG. SCI., 58:46-54,

Section: D‐lft Processmentioning

confidence: 99%

Thermal properties of glass fiber reinforced polyamide 6 composites throughout the direct long‐fiber reinforced thermoplastic process

Whitfield

Kuboki

Wood

et al. 2017

“…Other studies conducted on the influence of moisture in PA6 [5, 6], where work with industrial waste consisting of glass fiber reinforced PA6 composites was dried for 3, 6, and 9 h before reprocessing, also showed that the reprocessing of this type of composite was viable, because satisfactory physical–mechanical properties are attained thereafter, which make them suitable for several applications where these properties are desirable. The drying period of 6 h was the minimum necessary time for the reprocessed material to present a good visual appearance.…”

Section: Introductionmentioning

confidence: 99%

Study of rheological, thermal, and mechanical behavior of reprocessed polyamide 6

Crespo

Parrés

Peydró

et al. 2012

The effect of reprocessing Polyamide 6 (PA6) has been studied in this paper. To simulate recycled PA, we reprocessed virgin PA through 5 cycles. The PA 6 has undergone mechanical, thermal and rheological characterization after the various cycles of reprocessing in order to evaluate the corresponding properties and correlate them with the number of cycles undergone.In order to widen our injection simulation analysis by computer (CAE: Computer Aided Engineering) of these new materials, it was necessary to determine the viscosity using a mathematical model; in this case the Cross-WLF, to determine the relevant parameters.Our results show that tensile strength, elongation at break and hardness remain practically constant, while the charpy impact decreases as the number of reprocessing cycles increases.The effects of reprocessing on the material may decrease the rheological properties; specifically the viscosity of the material decreases with increasing processing cycles. The thermal properties are also influenced with the reprocessed material. The crystallinity increases and the degradation reaction will be advanced to increase the reprocessing cycle.

“…Nevertheless, recycling usually yields polymeric products with inferior properties to the original materials. This inferiority is because recycled plastic products accumulate thermal and mechanical history and contain the remains of polymeric additives, residual contaminants, labels, and dirt . Despite their scientific and practical importance, the limits of the thermal stability of these polymers are still not well understood.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Early Degradation Mechanisms of High‐Density Polyethylene, Polyamide 6 (Nylon 6), and Polyethylene Terephthalate

Sustaita‐Rodríguez

Medellín‐Rodríguez

Olvera‐Mendez

et al. 2019

The thermal stability and degradation mechanisms of three semicrystalline polymers (polyethylene terephthalate [PET], high-density polyethylene [HDPE], and polyamide 6 [nylon 6]) were studied. Thermogravimetric traces were acquired first at heating rates of 1 C/min and 10 C/min, and it was determined that the heating rate significantly affected the thermal decay curves of the three polymers. The results allowed the selection of specific temperatures at which to carry out heating and cooling cycles from room temperature to the molten state. The thermal behaviors of HDPE, nylon 6, and PET each had particular characteristics. HDPE showed the highest thermal resistance, whereas nylon 6 displayed the lowest. PET had the lowest activation energy for degradation, 93.5 kJ/mol, and retained 14 wt% after thermal recycling with no influence of molecular weight. Thermal cycling also revealed gradual morphological changes in HDPE, nylon 6, and PET, and their crystals changed from regular to branched spherulites with variations in the nucleation patterns. Fourier-transform infrared spectroscopy measurements allowed us to explain the early stages of degradation for each polymer. POLYM. ENG.