PLLA-TAP - GPC data

PLLA-TAP – GPC data 1.1.Materials A commercial PLLA grade, Luminy® L-130, with l-isomer content ≥ 99% and melt-flow index of 23 g/10 min (210 °C/2.16 kg), was kindly provided by TotalEnergies Corbion (The Netherlands). Triallyl phosphate (TAP) was purchased from TCI America as GC-grade with purity of 96%. Dicumyl peroxide (P) was purchased from Sigma-Aldrich with a purity of 98%, acetone from Romil as HPLC grade solvent. 1.2. Synthesis of long-chain branched PLLA Operators: Aniello Staiano, Valentina Marturano, IPCB-CNR. Before processing, PLLA pellets were dried overnight under vacuum at 60°C. Preparation of branched PLLA began with a pre-batch, by mixing dicumyl peroxide, triallyl phosphate and dried PLLA pellets in acetone, in order to promote adsorption of the reagents on the pellets surface. After complete evaporation of acetone, the pre-preg polymer pellets were further dried in at 60 °C under vacuum to remove traces of residual acetone, and of humidity. Reactive mixing was carried out using a Brabender Plastograph EC (Brabender GmBH & Co.KG, Germany), at 180°C and mixing rate of 100 rpm for 6 minutes. Plain PLLA pellets were also processed using the same protocol. Various formulations were prepared, by fixing peroxide content at 0.2 wt%, while varying TAP from 0.1 to 0.4 wt%, as detailed in Table 1, which also presents sample codes. Table 1. Sample codes and compositions Sample code PLLA (g) P (g) TAP (g) PLLA 100 0 0 TAP01 100 0.2 0.1 TAP02 100 0.2 0.2 TAP04 100 0.2 0.4 1.3.Gel permeation chromatography Operator: Giovanni Dal Poggetto, IPCB-CNR. Gel permeation chromatography (GPC) analyses were performed with a Omisec Resolve&Reveal equipped with a multidetector array composed by with refractive index (RI), right angle laser light scattering (RALS), low angle laser light scattering (LALS) and intrinsic viscosity (IV) detectors. Samples were dissolved in CHCl3 (Romil), filtered on 0.22µm PTFE membrane and eluted at flux of 0.8 ml min-1, runtime 50 min with injection volume of 100μl and a concentration of 5mg ml-1. Analyses were carried out using a column set composed of one pre-column and two Phenogel Phenomenex columns with exclusion limits 106 and 103 Da. Temperature of columns and detectors was set at 35°C. All samples were evaluated using triple point calibration, which provides absolute molecular weights, with polystyrene standard (Mn = 101.252 kDa and Mw = 104.959 kDa). All measurements were performed in duplicate. The data report intrinsic viscosity (IV) of melt-processed PLLAs, as a function of retention volume.