Jute fiber with high content and large aspect ratio is directly used to prepare PLA composites to show the effect on structure and properties. By comparing with bamboo powder, it is found that the large aspect ratio of jute fiber is helpful to form a crisscross structure in PLA composites to provide a strong framework. And the larger amount of jute fiber leads to the stronger framework in the PLA composites. Accordingly, the high comprehensive mechanical properties are produced of the PLA composites with jute fiber. Only through the simple blending of 70% jute fiber and PLA, the flexural strength and flexural modulus respectively reach 94.0 ± 4.4 MPa and 9116.7 ± 127.2 MPa, which obviously exceed the mechanical properties of PLA/bamboo blends. The addition of jute fiber also improves the thermal resistance of PLA composites as well as the crystallization ability and perfection of PLA. All the results exhibit the advantages of high content filling of jute fiber with large aspect ratio to modify PLA. Utilization of biomass filler with high content and large aspect ratio will provide an important methodology to expand the application capacity of fully degradable composites in many areas.

In this paper, large‐size reeds were introduced into PBAT to prepare high‐performance biodegradable composites by high‐speed blending without compatibilizer. Subsequently, the effects of large‐size reeds on the composite properties and biodegradation behavior were further investigated. The length of the reed in composites reaches to ~1.88 mm. It was found that all composites showed larger modulus and flexural strength than PBAT, and a significant increase in heat deflection temperature. By mixing 60% reed and PBAT, the bending strength, bending modulus, and heat deflection temperature reached 23.9 ± 0.4 MPa, 1237 ± 143 MPa, and 71.8°C, respectively. Biodegradation tests showed that the primary bond‐breaking site of PBAT was the C=O group. Compared with pure PBAT, the composites exhibited more significant mass loss, decreased thermal stability, increased melting point, and decreased crystallinity during degradation. A surface erosion degradation model for the composites was proposed. The research provides a scientific basis for applying high‐performance biodegradable composites to biodegradable blister and injection molded products.