Overview of Bio-based Materials

The core concept of bio-based materials—a burgeoning field—is gradually becoming a new favorite in both technology and environmental protection. This concept not only represents a new type of green and eco-friendly material but also embodies a comprehensive transformation of the entire industrial chain, from raw materials to finished products. By gaining a deeper understanding of the properties, sources, and applications of bio-based materials across various sectors, we can more fully grasp the future development trends in this field. According to the standard GB/T 39514-2020, “Definition, Terminology, and Labeling of Bio-Based Materials,” bio-based materials are those produced from biomass through biological manufacturing or synthesis processes, including bio-based chemicals and polymeric materials. These materials encompass not only basic bio-based chemicals such as bioalcohols and organic acids but also bio-based polymers, plastics, chemical fibers, rubber, coatings, and various additives and composite materials. Biomass, serving as the raw material for bio-based materials, broadly refers to organisms generated via photosynthesis—such as plants, animals, and microorganisms—as well as materials derived from them, including grains, straw cellulose, and agricultural waste.

Bio-based materials can be defined by referring to the standard GB/T 39514-2020. These materials primarily refer to various types of substances obtained through biological manufacturing or synthesis, as well as processing and refining, using biomass as a raw material. Biomass, serving as the raw material for bio-based materials, broadly encompasses organisms produced via photosynthesis—such as plants, animals, and microorganisms—as well as materials derived from them.

Classification and Applications of Bio-based Materials
Standard GB/T 39514-2020 provides a detailed classification of bio-based materials in Table A.1. These materials include not only polymers, plastics, chemical fibers, rubber, coatings, and other macromolecular or high-molecular-weight materials, but also the raw materials used to synthesize these macromolecules—such as small-molecule bio-based chemicals like ethanol, lactic acid, and ethylene glycol. Bio-based materials are categorized into polymers, plastics, fibers, and more, and are widely used across various fields. Thanks to their biodegradability, they have become a cornerstone of environmentally friendly materials. The commonly encountered types of bio-based materials are diverse, encompassing polymers, plastics, chemical fibers, rubber, coatings, and other macromolecular or high-molecular-weight materials, as well as the small-molecule bio-based chemicals—such as ethanol, lactic acid, and ethylene glycol—that serve as feedstocks for synthesizing these macromolecules.

Bio-based materials represent a broad category that encompasses chemicals as well as polymeric materials such as plastics, rubber, and fibers. Among these materials, bio-based plastics have attracted considerable attention due to their wide range of applications and mature technologies.

Exploring Bio-based Plastics

Common bio-based plastics
Next, we will take the commonly used bio-based plastics PBS/PBAT as an example to explore in detail their synthesis methods and related technologies. Bio-based plastics such as PBS/PBAT have attracted considerable attention due to their biodegradability; research in this area is particularly active at the Chinese Academy of Sciences and Tsinghua University. PBS/PBAT, or polybutylene succinate-co-polybutylene adipate terephthalate, is a type of biodegradable plastic. Its synthesis methods mainly include direct esterification, transesterification, and chain-extension reactions. Among these, direct esterification is the most widely used method in industrial applications.

In addition, the transesterification method is also an important synthetic approach. Research on PBS/PBAT is quite active in China, with institutions such as the National Engineering Research Center for Engineering Plastics at the Institute of Physical Chemistry of the Chinese Academy of Sciences and Tsinghua University taking a leading role.

The development prospects of bio-based materials
As public awareness of environmental protection continues to grow and the demand for alternatives to conventional plastics becomes increasingly urgent, the prospects for bio-based materials are looking ever brighter. With rising environmental consciousness, bio-based materials—thanks to their green substitution potential—are poised to capture a significant market share over the next decade. Compared to the global plastics industry’s massive production capacity of nearly 400 million tons, the emerging bio-plastics sector still appears relatively underdeveloped in terms of capacity; however, its growth potential cannot be overlooked.

Specific types of bio-based plastics

PBS/PBAT
PBS/PBAT is a biodegradable plastic synthesized via esterification. Extensive research has focused on increasing its molecular weight and reducing side reactions. Among these methods, the direct esterification process is the most widely used in industrial applications. This method first involves esterifying succinic acid with an excess of butanediol at a relatively low temperature. Subsequently, polycondensation is carried out under high temperature, high vacuum, and in the presence of a catalyst, thereby yielding PBS.

PLA polylactic acid
PLA is prepared via an indirect method using lactic acid as a raw material. Due to its high molecular weight and easily controllable processing, it has become widely used in industrial applications. PLA, or polylactic acid, is synthesized from lactic acid or its derivative, lactate esters. The polymerization process can be divided into two main methods: direct synthesis and indirect synthesis. Currently, the indirect method is the one predominantly employed in industrial production.

PHA Polyhydroxyalkanoate
PHA materials feature diverse monomer structures, and their successive generations have seen gradual improvements in performance, thereby broadening their range of applications. As a general term for polyhydroxyalkanoate materials, their monomers are predominantly 3-hydroxy fatty acids. PHB, the first-generation PHA product, although possessing some degree of biodegradability, suffers from significant brittleness.

PHA Polyhydroxyalkanoate
PHA materials feature diverse monomer structures, and their successive generations have seen gradual improvements in performance, thereby broadening their range of applications. As a general term for polyhydroxyalkanoate materials, their monomers are predominantly 3-hydroxy fatty acids. PHB, the first-generation PHA product, although possessing some degree of biodegradability, suffers from significant brittleness.

PEF polyethylene furanoate diethylene glycol ester
PEF material is derived from biomass monomers and boasts excellent performance as well as biodegradability, making its future prospects extremely promising. PEF, short for polyethylene furanoate, is a material characterized by outstanding physical properties and biodegradability.