1. Application Demands & Key Metrics

(1) Sector-specific Challenges

• Automotive: Components face -40°C~120°C cycles, UVB (≥0.68W/㎡), salt spray, and chlorides. E.g., mirror housings without proper treatment chalk and fade (delta E>5).

• Construction: Profiles need stability in acid rain (pH≤4.5), high humidity (RH≥90%). Unoptimized PVC loses >40% tensile strength after 5,000h aging.

• New Energy: PV junction boxes require UL94 V-0 and 100MΩ insulation after 1,000h at 85°C/85%RH; ABS hydrolyzes here.

  
  

  

(2) Performance Benchmarks

• Aging Test: Xenon arc (340nm, 1.2W/㎡) yields ΔYI≤5 and tensile retention ≥85%.

• Thermal Stability: DSC shows OIT≥20min at 200°C for high-temp use.

2. Base Material & Reinforcement Selection

(1) Polymer Matrices

• PC: 90% transparency, 60kJ/㎡ impact; add 0.3-0.5% UV absorbers for optics.

• PP: 0.91g/cm3, chemical-resistant; 0.2% HALS prevents oxidation for auto parts.

• PEEK: 316°C HDT, radiation-resistant; 30% CF composites for industrial use.

(2) Reinforcement Modification

• Glass fiber treated with KH-550 boosts PP/GF bond by 40%, wet strength retention to 82%.

• 2-3% nano-TiO? in PC shields UV and raises HDT by 10-15°C.

3. Additive Synergy & Process Control

(1) Photostabilization & Hydrolysis Resistance

• UV+HALS: 1:1.5 UV-328/HALS-944 in PE lifts elongation retention from 52% to 78% after 5,000h.

• NBC in ABS: 0.1-0.2% quenches peroxides, raises aging strength by 15-20%.

• PA66 end-capping: 0.5% caprolactam cuts hydrolysis loss from 3.2% to 1.1%.

(2) Molding Optimization

• PC temp: 280-300°C (avoid >320°C degradation), 80-100°C mold for stress reduction.

• PA6 annealing: 120°C/2h removes 90% stress, cuts cracking risk by 70%.

4. Green & Smart Innovations

• Biobased PLA: Grafted MAH +1% montmorillonite extends outdoor life to 12 months.

• Halogen-free FR: 3:7 MPP/ATH in PP meets UL94 V-0, avoids UV gas release.

• Self-healing PU: DCPD microcapsules repair 85% of UV-induced cracks.

5. Conclusion