In this work, the miscibility of a PHB formed by high and low molar mass fractions and a low molar mass PLA was studied. The extruded materials were analyzed by differential scanning calorimetry (DSC), dielectric spectroscopy (DS) and dynamic mechanical analysis (DMA). From these results, it was observed an unique behavior from the PHB fractions, and the partial miscibility of PLA onto low molar mass PHB.
PHB, PLA; blends, biodegradable polymer
| Rotação (RPM) | Torque (%) | Pressão (Psi) | Temperatura (°C) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Z1 | Z2 | Z3 | Z4 | Z5 | cabeçote | fundido | |||
| 200 | 55 | 400 | 170 | 170 | 169 | 169 | 165 | 165 | 165 |
| PHB | PHB/PLA (75/25) | PHB/PLA (50/50) | PHB/PLA (25/75) | PLA | |||
|---|---|---|---|---|---|---|---|
| Primeiro Aquecimento | |||||||
| Tm PHB (°C) | 171 | 171 | 171 | 172 | -------------- | ||
| ΔH (Jg–1) | 70 | 64 (b) | 60 (b) | 52 (b) | |||
| Tg PLA (°C) | - | 44 | 51 | 50 | 55 | ||
| ΔH (Jg–1) | 0,3 | 0,2 | 0,3 | 0,4 | |||
| Tcc PLA (°C) | - | 108 | 106 | 98 | 114 | ||
| ΔH (Jg–1) | –6 | –14 | –22 | –35 | |||
| Tm PLA (ºC) | - | 171 | 171 | 172 | 171 | ||
| ΔH (Jg–1) | 64 (b) | 64 (b) | 52 (a) | 53 | |||
| Segundo Aquecimento | |||||||
| Tg PHB (°C) | –2 | –2 | –2 | –4 | - | ||
| ΔH (Jg–1) | 0,4 | 0,3 | 0,2 | 0,1 | |||
| Tcc PHB (°C) | 56 | 64 | 70 | (a) | - | ||
| ΔH (Jg–1) | –39 | –30 (a) | –22 (a) | ||||
| Tm PHB (°C) | 172 | 172 | 171 | 166 / 173 | - | ||
| ΔH (Jg–1) | 62 | 60 (b) | 51 (b) | n.d. / 34 (b) | |||
| Tg PLA (°C) | - | (a) | (a) | 56 | 59 | ||
| ΔH (Jg–1) | 0,2 | 0,4 | |||||
| Tcc PLA (°C) | - | (a) | (a) | 114 | 117 | ||
| ΔH (Jg–1) | –30 | -35 | |||||
| Tm PLA (°C) | - | 172 | 171 | 166 / 173 | 171 | ||
| ΔH (Jg–1) | 60 (b) | 51 (b) | n.d. / 34(b) | 44 | |||
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