Study of the Thermomechanical Properties of Photocured Resins Based on Curable Monomers from PLA and PHB for SLA 3D Printing

Biobased curable structures were synthesized from polymers poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB). The curability of synthesized products and their thermomechanical properties were studied using numerous methods: FT-IR, DSC, DMA, or TGA. The reactivity of all methacrylated esters of lactic and 3-hydroxybutanoic acid was studied via DSC, and the results confirmed that all structures could be cured. The highest activation energy (E-a) was calculated for methacrylated methyl lactate, reaching 134.3 kJ<middle dot>mol(-1). It was also found that all calculated activation energies had very similar values. Infrared spectroscopy was used for the study of the degrees of cure. Curable alkyl lactates exhibited significantly higher degrees of cure (approximately 95% or more) than curable 3-hydroxybutarytes (around 70%). DMA analysis confirmed that methacrylated lactates showed higher glass transition temperatures (67.1 and 49.4 degrees C) and storage modulus values at 40 degrees C (1840 and 1110 MPa) compared to methacrylated 3-hydroxybutyrates (T-g of 44.4 degrees C and lower, and storage modules E ' around 600 MPa). The heat-resistant index calculated for all products proved the same trend: curable lactates exhibited higher heat resistivity (T-S of 148.0 and 146.3) than curable 3-hydroxybutyrates (T-S of 129.9 and 125.1). Synthesized and studied precursors can serve their particular purposes in fields of curable systems, and the application potential was performed via SLA 3D printing.