Table 2.
Toughness modification.
| Method | Ratio PLA/PBS | Modifier | Ratio Polymer/Modifier | Test Specimen | Morphology, Crystallization, and Mechanical Properties | Ref |
|---|---|---|---|---|---|---|
| Plasticiz. | 80/20 | Isosorbide diester (ISE) | 100:15 | Extruded flat films, 180–205 °C, 787 rpm, thickness: 20–50 µm | Porous structure ↓; presence of holes and defects ↓; cold crystalliz. temp.↓ for 21 °C; Tg ↓ from 55.3 to 34.7 °C; elongation at break: 250%. MOE: 511 MPa; TS: 19.8 MPa. | [41] |
| Plasticiz. | 80/20 | Poly (ethylene glycol) (PEG) | 100:10 | Injection-molded dumbbell at 220 °C, thickness: 3 mm | Tg of PLA ↓ significantly, crystallization rate of PLA ↓, elongation at break ↑ slightly. | [36] |
| Reactive compat. | 90/10 | Lysine triisocyanate (LTI) | 100:0.5 | Injection-molded samples at 220 °C, mold: 30 °C, 40–60 MPa, *1 | Particle number ↑; particle size ↓; elongation at break ↑ to >150%. impact strength ↑ 3-fold than that of PLA. | [42] |
| Reactive compat. | 80/20 | Benzoyl peroxide (BPO) | 100:1 | Hot-pressed sheets, at 160 °C, 3 min, then cold-pressed at room temperature, thickness: 0.5 mm | No phase separation; smooth surface; crystallinity ↓ due to cross-linking; elongation at break ↑ to about 400%, TS: little change. | [43] |
| Reactive compat. | 80/20 | Dicumyl peroxide (DCP) | 100:0.3 | Pressed tensile bars, at 180 °C, 10 MPa, thickness: 0.6 mm | PBS domain size ↓; isothermal crystallization time ↓; TS ↑ from 55 to 80 MPa, elongation at break ↑ from 49 to 205%. | [48] |
| Reactive compat. | 80/20 | Dicumyl peroxide (DCP) | 100:0.2 | Injection-molded specimens, cylinder 170–200 °C, die: 195 °C, mold: 25 °C, *1 | PBS domain size ↓; improved dispersion of PBS in PLA matrix; TS & MOE slightly ↑; elongation at break ↑ >400%. | [44] |
| Reactive compat. | 80/20 | Dicumyl peroxide (DCP) | 100:0.1 | Compression-molded sheets, thickness: 1 mm, at 170 °C, 8 min | PBS domain size ↓; uniform morphology; no nucleating effect on PLLA; elongation at break (250%): no change; impact strength ↑ for 8 times. | [16] |
| Reactive compat. | 70/30 | Methylene diphenyl diisocyanate (MDI) | 100:5 | Compression-molded tensile bars, at 180 °C, mold: 50 °C, 5 MPa, *1 | Morphology: uniform, no cavities or obvious phase separation TS & MOE ↓ slightly; elongation at break ↑ to 285%. |
[46] |
| Reactive compat. | 75/25 | Twice functionalized organoclay (TFC) with epoxy groups | 100:2 | Hot pressed specimens: 10 mm × 50 mm × 1 mm | PBS domain size ↓ from 1.8 to 0.59 µm, when TFC at 2 phr; tensile modulus ↑ from 1075 to 1407 MPa; elongation at break ↑ from 72 to 76%. | [49] |
| Reactive compat. | 50/50 | Glycidyl methacrylate (GMA) | 100:10 | Compression-molded sheets, 0.25 mm thick, 120 bar, 140–190 °C | Fibril formation before tensile fracture of the sheets; miscibility ↑; crystallinity ↓ due to crosslinking; elongation at break ↑ >4000 times. |
[47] |
| Copolym. | 80/20 | Random copolymer rPBSL | 100:5 | Blown film, thickness: 40 µm, extruder: 100–175 °C, 80–100 rpm | Smooth surface without droplets; Tg ↓ from 52 to 43 °C; Tc ↓ from 103 to 85 °C; crystallinity ↑ from 22 to 34%; spherulite growth rate ↑; elongation at break ↑ for 4 times. |
[23] |
| Copolym. | 80/20 | Linear block copolymer PLLA40-b-PBS28-b-PLLA40 | 100:3 | Compression-molded film, thickness: 40 µm | Smooth surface; formation of uniform spherulites; isothermal crystallization ↑; Transmittance (clarity) ↑; Tg ↓ to 20 °C; elongation at break ↑ for 2-fold. | [37] |
| Copolym. | 70/30 | Linear block copolymer PLLA37.5-b-PBS25-b-PLLA37.5 | 100:20 | Compression-molded sheets, at 180 °C, 10 MPa, thickness: 1 mm | PBS domain size ↓; elongation at break ↑ from 26% to 75%. | [45] |
| Copolym. | 70/30 | 3-arm block copolymer (PLLA-b- PGMA)3 | 100:2 | Compression-molded sheets at 180 °C, 10 MPa, thickness: 1 mm | PBS domain size ↓; uniform surface; cavities almost disappeared; elongation at break ↑ from 26% to 85%. |
[45] |
| Copolym. | 70/30 | Linear block copolymer + branched copolymer | 100:20:2 | Compression-molded sheets, at 180 °C, 10 MPa, thickness: 1 mm | No obvious phase separation, uneven fracture surface; elongation at break ↑ up to 250%. | [45] |
Legend: MOE: modulus of elasticity; TS: tensile strength; Tc: crystallization temperature; Tg: glass transition temperature; *1: no specification thickness given.