Research Progress in the Application of Maleic Anhydride (MAH) Grafting Technology in Polymer Alloys

I. Technical Principles and Reaction Mechanisms

The core of maleic anhydride (MAH) grafting technology lies in introducing polar functional groups into polymer molecular chains through chemical reactions. This technology primarily utilizes a free radical reaction mechanism. Under the action of initiators (such as dicumyl peroxide DCP or benzoyl peroxide BPO), active free radical sites are first generated on the polymer main chain. These active sites then undergo grafting reactions with MAH molecules, forming side-chain structures containing carboxylic anhydride groups.

Studies have shown that factors such as reaction temperature, initiator type and concentration, and MAH dosage significantly affect grafting efficiency. For polyolefin materials, the optimal reaction temperature is typically controlled within the range of 160–190°C, and a grafting rate of 0.5%–2% yields the best modification results. It is worth noting that process conditions must be strictly controlled during the reaction to avoid side effects such as excessive cross-linking or molecular chain degradation.

In recent years, advanced characterization techniques such as in-situ Fourier-transform infrared spectroscopy (FTIR) and electron spin resonance (ESR) have enabled researchers to gain deeper insights into the kinetic processes and mechanisms of grafting reactions.

II. Typical Application Cases and Performance Improvement Effects
MAH grafting technology has achieved multiple successful applications in the field of polymer alloys.

Automotive Lightweighting:
A renowned automotive manufacturer used MAH-grafted modified PA6/PP alloy to prepare door inner panel support components, achieving a 15% weight reduction while significantly enhancing material performance. Test data showed that the modified material’s tensile strength increased from 32 MPa to 45 MPa, a 40.6% improvement, and its notched impact strength rose from 6.5 kJ/m² to 9.1 kJ/m², a 40% increase. Additionally, the material maintained good toughness even in low-temperature environments of -30°C.

Eco-Friendly Packaging:
Researchers applied MAH grafting technology to PLA/PBAT biodegradable blend systems. By introducing a grafting rate of 0.8%, the interfacial bonding strength between the two incompatible polymers increased by 300%. The resulting film material’s tear strength reached three times that of unmodified systems, while fully retaining the material’s compostable degradation characteristics.

These successful cases fully demonstrate the technology’s exceptional effectiveness in improving material interfacial compatibility and overall performance.

III. Key Technical Challenges and Innovative Solutions
Despite significant progress, MAH grafting technology still faces several technical bottlenecks:

Side Reaction Control: High-temperature processing conditions can easily lead to molecular chain breakage or excessive cross-linking, resulting in degraded material performance.

Process Environmental Issues: Traditional solution-based grafting processes require the use of large amounts of organic solvents.

To address these issues, several innovative solutions have emerged in recent years:

The use of supercritical CO₂-assisted grafting technology enables efficient grafting under mild conditions while avoiding solvent use.

The development of novel composite initiation systems, such as peroxide/co-initiator combinations, can reduce the reaction temperature by 20–30°C.

The introduction of online monitoring systems for reactive extrusion allows dynamic optimization of process parameters by real-time detection of melt rheological properties and infrared spectral characteristics.

Additionally, molecular design to develop MAH derivatives with higher reaction selectivity is an effective approach to improving grafting efficiency. These innovations not only address existing technical challenges but also significantly enhance the economic and environmental benefits of the process.

IV. Future Development Trends and Market Prospects
With the growing demand for new materials, MAH grafting technology is facing new development opportunities.

Technical Level:

Intelligent modification will become an important direction. By integrating machine learning algorithms and big data analysis, autonomous optimization and prediction of process parameters can be achieved.

Multifunctional modification is also gaining attention. For example, combining MAH grafting with nanofillers (such as graphene and carbon nanotubes) can simultaneously endow materials with enhanced, conductive, flame-retardant, and other multiple properties.

Application Level:

The technology shows great potential in high-end fields such as new energy vehicle battery casings, low-dielectric materials for 5G communication equipment, and medical biodegradable implant materials.

Market research data indicate that the global market for MAH-grafted modified materials is growing at an average annual rate of 8–10% and is expected to exceed $2 billion by 2025. Particularly in the Asia-Pacific region, the demand for this technology is growing more significantly due to the rapid development of the automotive and electronics industries.

In the future, with the widespread adoption of green manufacturing concepts and the increasing demand for high-end materials, MAH grafting technology will undoubtedly play a key role in more fields.