Thermal and Mechanical Behavior of Elastomers Incorporated with Thermoregulating Microcapsules

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE center dot EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin(R)RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE center dot EVA-RT27).

Automated summary

Polyurethane (PU) is a principal polymer in the global plastic market due to its versatility and continuous improvement. In this study, PU elastomeric materials with thermoregulating properties were produced by incorporating microcapsules (mSD-(LDPE center dot EVA-RT27)) containing paraffin(R)RT27 into the matrix. The density and tensile strength decreased with increasing microcapsule content, with E-1.05 showing better structural and stability properties for microcapsule contents up to 15 wt.% and E-1.1 displaying mechanical and thermal synergy effects with 20 wt.% microcapsule content.