Research and Application of Bio-based Compatibilizers: Breakthroughs in Molecular Design Drive the Development of Biodegradable Plastics | Jiuju Polymer

Abstract:

This article systematically analyzes technological innovations, breakthroughs in molecular structure design, and the application effectiveness and market potential of bio-based compatibilizers in the field of biodegradable plastics. The study finds that, with the tightening of global environmental regulations and the advancement of the "dual-carbon" goals, bio-based compatibilizers are transitioning from the laboratory to industrialization. Innovative molecular design significantly enhances the interfacial properties and degradability of blended materials such as PLA/PBAT. In 2025, the market size of bio-based compatibilizers in China is projected to reach 2.5 billion yuan, with an annual growth rate exceeding 40%. Domestic enterprises are accelerating the replacement of foreign brands through comprehensive industry chain layouts and technological breakthroughs. However, the industry still faces challenges such as high costs, technical barriers, and certification standards, requiring collaborative innovation between industry, academia, and research, along with policy support to promote sustainable development.

Keywords: Bio-based compatibilizer; Molecular design; PLA/PBAT blend; Biodegradable plastics; Environmental regulations

1. Introduction

Compatibilizers are key additives for the modification of polymer materials, significantly improving the mechanical properties, processing performance, and weather resistance of composite materials by enhancing the interfacial compatibility between different polymers. Against the backdrop of the transition from traditional plastics to biodegradable materials, bio-based compatibilizers have gradually become the focus of industry attention due to their environmental friendliness and renewability. According to data from CRI Industry Research, China's compatibilizer market size is expected to exceed 12 billion yuan in 2025, with bio-based compatibilizer demand growing by 50% annually, and its market share expected to reach 18%.

Through innovative molecular design, bio-based compatibilizers can effectively address the issue of interfacial separation during the blending of biodegradable materials such as PLA, PBAT, and PHA, while meeting the strict requirements of environmental regulations regarding material degradability and biocompatibility. This article focuses on the technological innovations, breakthroughs in molecular structure design, and the application effectiveness and market potential of bio-based compatibilizers in the field of biodegradable plastics, aiming to provide industry researchers with professional and detailed technical and market insights.

2. Technological Innovations and Breakthroughs in Molecular Structure Design of Bio-based Compatibilizers

2.1 Main Technological Paths and Innovation Directions

The core technology of bio-based compatibilizers revolves around molecular structure design, currently forming three main directions:

Upgrading of Traditional Systems: Traditional compatibilizers represented by maleic anhydride grafted polypropylene (PP-g-MAH) are iterating towards higher heat resistance and lower odor by optimizing grafting rate and purity. The low residual monomer technology developed by Kingfa Science & Technology reduces VOC content in products, meeting stringent environmental requirements for automotive interiors.

Breakthroughs in Functionalized Systems: Novel grafting technologies such as epoxy-based, acrylate-based, and silane coupling agents are emerging for high-end application scenarios. For example, epoxy-based compatibilizers enhance the interfacial bonding between nylon and polyphenylene ether through chemical bonding, significantly improving the heat resistance of components around automotive engines. Silane coupling agents significantly enhance the compatibility between glass fibers and resin matrices through hydrolysis-condensation reactions, widely used in the lightweight design of 5G communication base station enclosures.

Rise of Bio-based Systems: With the global upgrade of plastic restrictions, bio-based compatibilizers based on polylactic acid (PLA) and polyhydroxyalkanoates (PHA) have become research hotspots. Graft modification using natural polymers such as starch and cellulose enables low-carbon footprints throughout the material's life cycle.

2.2 Molecular Structure Design and Synthetic Method Innovations

Block Copolymer Design: The molecular structure design of bio-based compatibilizers primarily employs block, graft, and star structures. Taking the PLA/PBAT blend system as an example, introducing itaconic anhydride grafted PP compatibilizer (BAH-g-PP) achieves a grafting rate up to 1.5%, far exceeding that of traditional maleic anhydride MAH-g-PP via twin-screw extrusion, while offering lower odor and good performance.

Controlled/Living Polymerization Techniques: Controlled polymerization techniques such as anionic, cationic living polymerization, and Atom Transfer Radical Polymerization (ATRP) enable precise control over the molecular weight and distribution of bio-based compatibilizers, reducing the Polydispersity Index (PDI) to 1.2-1.5. This increases the Melt Flow Rate (MFR) from the traditional 10g/10min to 15g/10min, boosts injection molding equipment speed by 20%, and reduces downtime for adjustments.

Conversion Synthesis: Synthesis methods converting from cationic polymerization to free radical or condensation polymerization have become a research hotspot for bio-based compatibilizers. For instance, Tuncai initiated the living cationic polymerization of isobutyl vinyl ether using trifluoromethanesulfonic acid/tetrahydrothiophene at -30°C. After a period of reaction, adding oligomeric ester diol with an azo group yielded a block copolymer of isobutyl vinyl ether and polyester.

Graft Modification Technology: Reactive compatibilizers like GMA grafts introduce reactive functional groups (e.g., epoxy groups) that undergo chemical reactions with polar groups (hydroxyl, carboxyl) of bio-based polymers, forming stable interfacial bonds. For example, the team of Shi Xinyan used PLA-g-GMA compatibilizer to increase the elongation at break of PLA/PBAT blends by over 100 times and significantly improved the interlayer bonding strength for 3D printing.

2.3 Latest Technological Breakthrough Cases

Itaconic Anhydride Grafted PP Compatibilizer: Developed by the Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, this itaconic anhydride grafted PP compatibilizer boasts a grafting rate as high as 1.5%, far surpassing traditional maleic anhydride grafted products, with significantly reduced costs. A thousand-ton production line has been established, providing key technical support for the industrialization of PLA/PBAT blend materials.

Low Die-Lip Buildup Biodegradable Composition: Two patents authorized to Kingfa Science & Technology in December 2025, titled "A Biodegradable Composition with Low Die-Lip Buildup, Its Preparation Method and Application," effectively solved issues of insufficient edge seal strength and die-lip buildup during the processing of biodegradable films, significantly enhancing product practicality.

In-situ Polymerization Technology: The reactive compatibilizer developed by Dawn Group, using an in-situ polymerization process, increased the impact strength of PA66/PP blend materials by 400%, replacing traditional maleic anhydride grafted compatibilizers and providing a new pathway for the application of bio-based materials in automotive lightweighting.

3. Application Effectiveness and Market Potential of Bio-based Compatibilizers in Biodegradable Plastics

3.1 Application Scenarios and Performance Evaluation

The application effectiveness of bio-based compatibilizers in biodegradable plastics is mainly reflected in the following aspects:

PLA/PBAT Blend Materials: Adding reactive compatibilizers like GMA can significantly improve the interfacial compatibility between PLA and PBAT. Research from Sichuan University showed that when adding 1 wt% carbon nanotubes (CNTs), the PLA/PBAT blend achieved maximum elongation at break, increased by 258.6% compared to samples without CNTs. Further research by Shi Xinyan's team indicated that PLA-g-GMA compatibilizer increased the elongation at break of PLA/PBAT blends from 21.9% before modification to 271.7%, while tensile strength changed from 13.4 MPa to 10.8 MPa, achieving significant performance improvement.

PHA-based Materials: The PHA-based biodegradable film bags developed by Bluepha Co., Ltd., through compatibilizer-optimized formulations, allow complete degradation under natural or composting conditions while maintaining good mechanical properties. Substituting 1 ton of traditional plastic with 1 ton of PHA can reduce pollutant emissions by 0.84 tons and achieve carbon emission reduction of 1250 tons/year (based on an annual production of 5000 tons).

Starch-based Materials: Modifying starch (CS)/PBAT blends with Gly/LiCl composite modifiers enhances electronic interactions between the modifier and starch hydroxyl/PBAT ester groups, disrupts starch hydrogen bonds and granular structure, reduces CS/PBAT crystallinity, and improves compatibility. Using a composite modifier with a Gly:LiCl mass ratio of 10:1 and a CS:PBAT mass ratio of 50:75, the modified CS/PBAT blend's elongation at break increased from 21.9% before modification to 271.7%, and tensile strength changed from 13.4 MPa to 10.8 MPa, showing good modification effects.

Medical Applications: The medical-grade compatibilizer developed by the Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, has passed FDA certification and been successfully applied in medical devices such as artificial heart valves, with biocompatibility reaching internationally leading levels.

3.2 Market Size and Growth Potential

Global Market: The global bio-based products market size is projected to reach $48.1 billion in 2025, with China being the global leader in the bio-based materials sector, with a market size of $23.1 billion, accounting for 48.02% of the global share. As an important component of bio-based materials, the market growth rate of bio-based compatibilizers far exceeds the industry average.

Chinese Market: China's compatibilizer market size was approximately 7.13 billion yuan in 2024 and is expected to exceed 12 billion yuan in 2025, nearly doubling compared to 2020, with a CAGR of 13.7%. Among this, the bio-based compatibilizer market is projected to reach 2.5 billion yuan, with an annual growth rate exceeding 40%. Its share of the total compatibilizer market is expected to increase from about 8% in 2020 to 18% in 2025.

Segmented Markets: In the biodegradable plastics field, bio-based compatibilizer applications are mainly concentrated in packaging, medical, and agriculture. Packaging is the largest application market, accounting for about 50% of the total biodegradable plastics market. Demand is expected to reach 1.25 million tons in 2025. With compatibilizer usage at 1%-3%, the market size could reach 1.25-3.75 billion yuan. Medical and agricultural sectors together account for 15%-20%, but with higher added value, they are important directions for future growth.

3.3 Cost and Supply Chain Analysis

The cost structure of bio-based compatibilizers differs significantly from traditional ones. Taking PLA-based compatibilizer as an example, its cost is mainly determined by raw materials (PLA), grafting monomers (GMA), and production processes. By 2025, with technological advancements and scaled production, the cost of PLA-based compatibilizer is expected to drop from 30,000 yuan/ton to 18,000 yuan/ton, a reduction of 40%, significantly enhancing market competitiveness.

Supply Chain Optimization: China's bio-based compatibilizer raw material supply mainly relies on bio-based polymer production. Sinopec has built the world's largest PLA production base, providing stable raw material supply for bio-based compatibilizers. Meanwhile, enterprises like Kingfa Science & Technology have achieved self-sufficiency in raw materials through a full industry chain layout of "bio-based monomer - polymerization - modification," reducing cost fluctuation risks.

Cost Reduction from Technological Breakthroughs: The application of itaconic anhydride grafting technology significantly reduces the production cost of bio-based compatibilizers; microencapsulation technology triples the controlled release efficiency of flame retardants, meeting the UL94 V-0 standard for new energy vehicle battery packs; in-situ polymerization technology increases the impact strength of PA66/PP blends by 400% while reducing processing energy consumption.

4. Impact of Policy Drivers and Industry Competition Landscape on Bio-based Compatibilizer Development

4.1 Policy Environment and Regulatory Requirements

National Policy Support: In January 2023, the Ministry of Industry and Information Technology and five other departments issued the "Three-Year Action Plan for Accelerating the Innovation and Development of Non-Grain Bio-based Materials," explicitly listing bio-based materials as key basic materials in the "New Material Industry Development Guide" and the "Strategic Emerging Industries Classification (2023)," providing policy support for bio-based compatibilizer development.

Upgraded Environmental Standards: In 2025, MIIT released the "Plastic Modification Additives Industry Standard Conditions," imposing stricter requirements on compatibilizers' environmental indicators (e.g., VOC content <500ppm, heavy metal limits ≤100ppm), production energy consumption, and quality stability, accelerating the of backward production capacity and promoting industry concentration.

Plastic Restriction Orders Implementation: According to the "Opinions on Further Strengthening Plastic Pollution Control," by 2025, consumption intensity of non-degradable disposable plastic tableware in the in cities at prefecture level and above should decrease by 30%; nationwide, postal and express delivery outlets are prohibited from using non-degradable plastic packaging bags, plastic tape, and disposable plastic woven bags; all hotels and will no longer actively provide disposable plastic. These policies directly drive an annual increase of 40%-50% in demand for bio-based compatibilizers.

International Certification Systems: The EU REACH regulation requires biodegradable plastics to meet the EN 13432 standard, demanding at least 90% disintegration after 12 weeks, at least 90% biodegradation within 6 months, and requiring ecotoxicity tests and heavy metal content detection. International standards such as the US BPI certification and Japan's GreenPla certification also impose strict requirements on bio-based compatibilizers, pushing the industry towards high-quality development.

4.2 Competitive Landscape and Market Dynamics

Market Concentration: In 2025, the global compatibilizer market presents a "pyramid" structure. The high-end market (e.g., medical-grade compatibilizers) is dominated by foreign companies like Dow Chemical, Arkema, and BASF, with a market share exceeding 60%. The mid-to-low-end market is led by domestic enterprises like Kingfa Science & Technology, Jiarong, and Nengzhiguang, with continuously increasing market share. In emerging fields (e.g., bio-based, biodegradable), domestic and foreign companies are on the same starting line. Domestic enterprises, leveraging policy support and cost advantages, are expected to achieve overtaking on curves.

Rise of Domestic Enterprises: Kingfa Science & Technology, as a leading domestic enterprise in the bio-based materials field, has built a full industry chain system of "bio-based monomer - polymerization - modification." Its bio-based succinic acid capacity reaches 50,000 tons/year, bio-based BDO capacity 10,000 tons/year, and biodegradable material sales reached 158,000 tons, approaching full capacity and achieving profitability. Its bio-based LCP material Vicryst® LCP CER-B is the first in China and second globally in the industry to pass the International Sustainability & Carbon Certification (ISCC) PLUS, marking a major breakthrough for Chinese enterprises in the high-end bio-based materials.

Industrial Cluster Formation: Nanle County in Henan and Guzhen County in Anhui serve as characteristic cluster zones, focusing on industries like biodegradable plastics and textiles; Hubei is laying out emerging fields such as bioenergy, including a 1 billion yuan non-grain bio-based production line in Xiangyang and the world's first production line in Jingzhou. As of July 2025, China had over 800 bio-based material enterprises, forming industrial clusters centered on the Yangtze River Delta and Pearl River Delta.

Changing Competitive Factors: Industry competition has shifted from to comprehensive solution competition. Technological R&D capability, customized service capability, and industry chain synergy have become core corporate competencies. For example, Kingfa Science & Technology builds upstream MAH production facilities to extend upstream or participates in customer material downstream, cost and technology.

4.3 Technical Barriers and Patent Distribution

Patent Application Trends: Global bio-based material patent applications grew by 31% from 2024 to 2025, with China contributing the most in the non-grain bio-based materials. However, regarding overall patent distribution, Japan, South Korea, and the US remain patent powerhouses in bio-based compatibilizers. Although China's application volume has declined recently, domestic enterprises are through technological breakthroughs.

Core Technology Patents: In 2025, core patents in the bio-based compatibilizer field mainly focused on:

Itaconic Anhydride Grafting Technology: The patent for itaconic anhydride grafted PP compatibilizer from the Ningbo Institute of Materials Technology & Engineering, CAS, with a grafting rate up to 1.5%, far exceeding traditional maleic anhydride grafted products.

Low Die-Lip Buildup Technology: Kingfa's patent for "A Biodegradable Composition with Low Die-Lip Buildup, Its Preparation Method and Application," solving key issues in biodegradable film processing.

In-situ Polymerization Technology: Dawn Group's patent for in-situ polymerization technology for PA66/PP blends, increasing impact strength by 400%.

Patent Regional Distribution: According to the 2025 Biodegradable Plastic Patent Analysis Report, among global biodegradable plastic patents, China's application volume has declined in recent years, but domestic enterprises (e.g., Kingfa, Cathay Biotech) are through technological breakthroughs. Japanese companies like Mitsubishi Chemical were early leaders but later declined, while Kaneka maintained competitiveness; European companies like BASF and Novamont are main innovation forces; South Korea's patent applications have grown significantly in the past five years.

5. Conclusion and Outlook

Bio-based compatibilizers, as a key technology to solve the interfacial compatibility issues of biodegradable materials, are undergoing a rapid transition from laboratory research to industrial application. Through innovative molecular design and synthetic technology breakthroughs, bio-based compatibilizers enhance the performance of blends like PLA/PBAT and PHA while meeting the strict requirements of environmental regulations on material degradability and biocompatibility.

Technological Development Trends: In the future, bio-based compatibilizers will develop towards high-performance, green, and customized. The application of synthetic biology will further reduce the cost of bio-based materials; microencapsulation technology will enhance the release efficiency of functional compatibilizers; in-situ polymerization technology will bring material performance to new heights. Simultaneously, AI-assisted molecular design will become an important tool for industry innovation, accelerating the R&D of new bio-based compatibilizers.

Market Prospect Outlook: With the tightening of global environmental regulations and the advancement of "dual-carbon" goals, the bio-based compatibilizer market will experience explosive growth. By 2030, the market share of bio-based compatibilizers is expected to increase significantly from the current 18% to over 30%, becoming the core engine for industry growth. Domestic enterprises, through full industry chain layout and technological breakthroughs, are expected to achieve comprehensive replacement in the mid-to-low-end market and form a competitive situation with foreign companies in the high-end market.

Challenges and Opportunities Coexist: Although the development prospects for bio-based compatibilizers are broad, challenges such as high costs, technical barriers, and certification standards remain. However, these challenges also provide development opportunities. Through industry-university-research collaborative innovation, enterprises can accelerate technological breakthroughs; through policy support, enterprises can reduce R&D and production costs; through international certification, enterprises can expand into global markets.

Industry Recommendations: For industry researchers and enterprise decision-makers, it is recommended to focus on the following directions:

Molecular Design Innovation: Deeply research the interaction mechanisms between the molecular structure of bio-based polymers and compatibilizers to develop efficient, low-residue new bio-based compatibilizers.

Industry Chain Integration: Strengthen the integration of upstream and downstream bio-based material industry chains, build a complete industrial ecosystem from raw materials to applications, and reduce production costs.

Policy Response: Closely monitor changes in domestic and international environmental regulations and industrial policies, adjust R&D and production strategies in a timely manner to seize market opportunities.

International Cooperation: Actively participate in international standard setting and certification system construction to enhance the international competitiveness of Chinese bio-based compatibilizers.

The future development of bio-based compatibilizers will profoundly influence the green transformation and sustainable development of the polymer materials industry. Through technological innovation and policy support, bio-based compatibilizers are expected to become an important tool in addressing plastic pollution, driving the materials industry towards a more environmentally friendly, efficient, and sustainable direction.