Dsc 1 differential scanning calorimeter

The molecular weight and molecular weight distribution of the PHAs were examined using a size-exclusion chromatograph (Agilent Technologies 1260 Infinity, Waldbronn, Germany) with a refractive index detector, and this was achieved using an Agilent PLgel Mixed-C column, where the weight average, M_w, number average, M_n and polydispersity (Ð = M_w/M_n) were determined. The thermal properties of the polymer were analyzed using a DSC-1 differential scanning calorimeter (Mettler Toledo, Schwerzenbac, Switzerland). The melting points were determined from the exothermal peaks in the thermograms using the STARe software. Thermal degradation of the samples was investigated using a TGA2 thermal analysis system (Mettler Toledo, Schwerzenbac, Switzerland). The theoretical degree of crystallinity was calculated using the following formula:
where ∆H_i is specific enthalpy of melting of the sample (J/g), and ∆H₀ is the specific enthalpy of a melted 100% crystallized P(3HB) (146 J/g) [67 (link)]. The methods for analyzing the physicochemical properties of PHAs have been previously described in detail [59 (link)].

To study the effect of MWCNT wt.% on the thermal characteristics of the EVA/MWCNT composites, DSC measurements were carried out using a DSC 1 differential scanning calorimeter (Mettler Toledo Inc., Columbus, OH, USA). Samples weighing about 8 mg were cut from the as-received EVA/MWCNT pellets. In order to remove the thermal history, samples were first heated from 25 °C to 180 °C at 10 °C/min and held at 180 °C for 5 min, and then cooled down to 30 °C at a cooling rate of 10 °C/min to obtain the non-isothermal crystallization curves. This procedure was repeated in a second run.

Characterization of the synthesized PLA and PLA–PEG
was carried
out on a DSC1 differential scanning calorimeter (Mettler Toledo).
The temperature cycle was set as follows: heating from −35
to 200 °C (rate: 10 °C/min), then 2 min heating at 200 °C,
and cooling to −35 °C (rate: 10 °C/min); this was
repeated after 2 min of maintained temperature. This procedure for
the measurement occurred under a nitrogen atmosphere.

The physicochemical properties of high-purity PHA specimens were determined using modern physicochemical methods, which have been described in detail elsewhere [41 (link),42 (link)]. Molecular-weight properties of the polymers (weight-average (M_w) and number-average (M_n) molecular weights and polydispersity (Ð)) were measured. Melting point (T_melt) and thermal degradation temperature (temperature at which sample mass loss begins, T_degr) were measured using a DSC-1 differential scanning calorimeter (Mettler Toledo, Schwerzenbac, Switzerland) and TGA (Mettler Toledo, Schwerzenbac, Switzerland), respectively. A 3–5 mg sample was heated to 200 °C at a rate of 5 °C/min; the sample was held at 200°C for 1 min, cooled to −20 °C at a rate of 5 °C/min and held for 4 min. Then, the sample was reheated at a rate of 5 °C/min (DSC). A 3–5 mg sample was heated to 450 °C at a rate of 10 °C/min (TGA). Thermograms were analyzed using the “StarE”software. X-ray examination was performed using a D8ADVANCE powder diffractometer (Bruker AXS, Karlsruhe, Germany) equipped with a VANTEC linear detector; the degree of crystallinity (C_x) was calculated as a ratio of the total area of crystalline peaks to the total area of the radiogram (the crystalline + amorphous components