Polymer melting temperatures and crystallinity at different pressure applied

Abstract

The present work aims at the experimental investigation of the effect of an increased thermal bonding pressure on the melting point (the so‐called Clapeyron effect) of three polymers employed in nonwovens. Namely, this work quantifies the dependence of melting temperature on pressure in these polymers. The following three polymers were used in the present experiments: polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and polypropylene (PP) (all three already received in the form of nonwovens). A simple novel method of measurements of melting points of such polymers under different pressures was proposed and developed. The results revealed: (i) the melting point of PBT nonwovens increased by about 12°C when the applied pressure was increased up to 277.79 atm; (ii) the melting point of the PET nonwovens increased by about 7°C when the applied pressure increased up to 104.86 atm; (iii) the melting point of PP nonwovens increased by about 6°C when the applied pressure was increased up to 104.86 atm. The melting temperature measurements by the present method were also validated through differential scanning calorimetry measurements with the above‐mentioned three polymers without applied pressure.

Structural Investigation on Electrospun Nanofibers from Postconsumer Polyester Textiles and PET Bottles

“…These data corroborate the values reported in previous studies. 6,7,28,29 Compared to the original postconsumer PET sources, the corresponding electrospun PET NF showed significantly lower %crystallinity (Table 1) and exhibited distinct glass transitions as well as cold crystallization behavior (Figure 2a,b). The decreased % crystallinity in the PET NF is attributed to the rapid evaporation of the highly volatile solvent system (TFA/ DCM) during the electrospinning process.…”

Trends in Polymer Degradation Across All Scales

“…Another remaining challenge is the processibility of enzymes, where working temperatures for plastic production often exceed 200 °C. [66,98,99] Developing future techniques that prevent enzyme denaturation, heat-tolerant enzymes or synthetic enzyme mimics might aid to solve this challenge.…”

“…Moreover the risk of allergic reactions has to be examined, since for instance, proteases sensitization is well known in the detergent industry [64] and amylase plays a main role in Baker's Asthma. [65] On a practical level, developing enzyme encapsulation or enzyme modification strategies to maintain stabilization above the 200 °C mark, which is often required for polymer processing, [66] needs to be addressed. While it may be intuitive to look to thermophilic enzymes, they are often found to have low catalytic activity at ambient temperature.…”

Structure–Property–Processing Relations of Short‐Chain Branched Poly(butylene terephthalate) (PBT) with Biobased Comonomers

“…Poly(butylene terephthalate) (PBT) and PBT-based materials are well-established engineering plastics with high durability, heat resistance, mechanical strength, dimensional and hydrolytic resistance, and other advantageous material properties. [1][2][3][4][5] The annual consumption of PBT reached 1.3 million metric tons in 2020, [6] and is expected to show a compound annual growth rate of 3.9-5.6% until 2029. [7] This trend is mainly caused by the increased demands of the electrical and automotive industries in particular for interior and exterior as well as near-the-engine parts of electrical vehicles with extremely high requirements.…”