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    Coupling agents are functional polymer bridges between polyolefin resins and incompatible materials. SI Group's POLYBOND™ 3200 is legendary for its performance as a coupling agent in thermoplastic and cellulose-fiber-filled applications. 

As a polypropylene-based coupling agent, POLYBOND™ 3200 outperforms the competition by demonstrating superior thermal stability, color control, and less degradation. Incompatible materials, including nonwovens, carpet tiles, composites, filled polypropylene, polypropylene–polyamide alloys, thermoplastic composites, cellulose, and natural-fiber-filled materials, can benefit from improved mechanical properties for better adhesion (coupling) to the base resin matrix. 



POLYBOND™ improves the potential compatibility of glass-fiber-filled polypropylene used in automotive interior applications. Glass-fiber-reinforced polypropylene composite materials offer lightweight, versatile, and superior performance, requiring an improved interfacial adhesion between the glass-fiber filler and the polypropylene composite.

Incorporating POLYBOND™ 3200 as a versatile compatibilizer provides the following improved mechanical properties:

1. Impact strength

2. Toughness

3. Retained lightweight characteristics

4. Flexural strength

5. Enhanced adhesion 

6. Improved filler dispersion

7. Increased tensile strength 

Increased Mechanical Properties 

    Increased Thermal Properties 

    Furthermore, flexural strength and heat distortion temperature (HDT) experience significant improvement corresponding to the enhanced coupling of the glass fiber to the polymer matrix. 

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    POLYBOND™ Advantage Why It Matters Benefit to You
    Advanced Production Technology Reduced degradation and black-speck formation Higher productivity and less waste
    Superior Color Stability No discoloration for sensitive white good applications Broader processing window for higher productivity
    Improved Heat Stability Increased durability, mechanical performance, and stronger compound protection Lower off-spec production
    SI Group Product Brand Controlled manufacturing process Less degradation and consistent product performance 

POLYBOND™ 3200 compatibilizer is ideal for formulators requiring natural or white-color resilience at elevated temperatures because of its outstanding color and thermal properties.

POLYBOND™ 3200 samples were compared to a competitor's coupling agent. After heat aging for 14 days at 150°C (302°F), POLYBOND™ 3200 maintains its color better than the competing coupling agent.

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    Before Heat Aging

    POLYBOND™ 3200 & Competitor
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    After Heat Aging

    POLYBOND™ 3200 & Competitor

The melt flow index (MFI) measured 9 for both grades before heat aging. After heat aging, POLYBOND™ 3200 retained its MFI while the competitor's product degraded.


Property Typical Value Test Based On
Appearance Off-white Pellet Visual
Melt Flow Rate @ 190°C, 2.16Kg 115 g/10 min ASTM-D1238
Maleic Anhydride Content High* ASTM D-6047
Specific Gravity @ 23°C 0.91 g/cm3 ASTM D-792
Bulk Density 0.6 g/cm3 ASTM D1895B
Melting Point 157°C DCS
CAS Number 9003-07-0

*Maleic anhydride content is typically in the range of 0.8% to 1.2%


Glass-fiber-filled polypropylene composites require a coupling agent to reinforce interfacial adhesion between the filler and the polymer matrix. POLYBOND™ 3200 improves the bond between the polyolefin and filler while enhancing the compound's thermal stability and tensile strength. Talk to one of our specialists to learn more or sample POLYBOND™ 3200 today. 




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