Study on preparation and properties of highly tough bio⁃based polylactic acid/polyurethane blends

doi:10.19491/j.issn.1001-9278.2025.07.001

Abstract

Abstract:

Bio⁃based thermoplastic polyurethanes （BPUs） were synthesized using bio⁃derived 1，5⁃pentanediyl diisocyanate and poly（1，3⁃propanediol）， with either isosorbide （IS） or a combination of IS and 3⁃allyloxy⁃1，2⁃propanediol （APD） as chain extenders. These BPUs were employed to toughen polylactic acid （PLA） via dynamic vulcanization. The influence of chain extender composition and structure on the toughening performance of PLA/BPU blends was systematically investigated. The PLA/BPU⁃IS/APD blend demonstrated superior mechanical properties， achieving tensile strength of 47.22 MPa， elongation at break of 133.8 %， and impact strength of 54.21 kJ/m²， while maintaining a high bio⁃based content of 99.4 %.

Key words: polylactic acid, polyurethane, bio?based materials, dynamic vulcanization, mechanical strength

CLC Number:

TQ321

LIU Lin, SHOU Tao, LIAO Feiyang, ZHENG Zikang, FENG Xinhe, ZHAO Xiuying. Study on preparation and properties of highly tough bio⁃based polylactic acid/polyurethane blends[J]. China Plastics, 2025, 39(7): 1-5.

Figures/Tables 11

Fig.1. Schematic diagram of BPU synthesis

样品编号	PO3G∶PDI∶IS∶APD	生物基含量/%	M_n/×10⁴ g/mol
BPU⁃IS	1∶1.63∶0.63∶0	100	6.7
BPU⁃IS/APD	1∶1.63∶0.315∶0.315	96.9	4.1

Tab.1. Formula and number⁃molecular weight of the samples

Fig.2. FTIR of BPU

Fig.3. Torque⁃time curves of PLA and PLA/BPU blends

Fig.4. Reaction mechanism during dynamic vulcanization

Fig.5. DSC curves of PLA and PLA/BPU blends

样品

$T g$ /

℃

$T c c$ /

℃

$Δ H c c$ /

J·g^-1

$T m$ /

℃

$Δ H m$ /

J·g^-1

$χ c$ /

样品

$T g$ /

℃

$T c c$ /

℃

$Δ H c c$ /

J·g^-1

$T m$ /

℃

$Δ H m$ /

J·g^-1

$χ c$ /

PLA

61.8

112.9

27.57

152.0

28.92

1.44

PLA/BPU⁃IS

61.2

125.1

17.79

153.2

19.25

1.95

PLA/BPU⁃IS/APD

61.6

126.8

14.15

153.7

15.80

2.20

Tab.2. DSC data of PLA and PLA/BPU blends

Fig.6. Dynamic rheological properties of PLA and PLA/BPU blends

Fig.7. Mechanical properties of neat PLA and PLA/BPU blends

断裂伸长率/

Tab.3. Mechanical properties data of PLA and PLA/BPU blends

Fig.8. SEM of impact fracture surfaces

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