Kenaf and polypropylene fibers interwoven

Kenaf-Polypropylene Composites: The Secret to Stronger, Eco-Friendly Materials?

Soraya Malik in Tech & Innovation December 2025 • 4 min read.

"Unlock the potential of prepreg composites by understanding how ply count, temperature, and pressure influence mechanical properties."

The world is increasingly turning towards composite materials, and natural fibers like kenaf are emerging as sustainable reinforcement options. These natural alternatives offer cost advantages and environmental benefits over traditional materials. For example, using natural fibers in automotive parts can cut energy consumption by a significant margin.

However, challenges remain. Natural fibers and polymer matrices often don't bond well due to differences in their properties. This is where coupling agents and treatments like alkali treatment come in, bridging the gap between fiber and matrix to enhance the material's overall strength.

Melt compounding is a common technique for creating natural fiber thermoplastic composites, but it's not always ideal for large-scale production. A promising alternative is the prepreg method combined with compression molding. This technique involves preparing polymer sheets beforehand, arranging them in a sandwich structure with the reinforcing fibers, and then fusing everything together under heat and pressure. Let’s dive into how this method affects the final product.

Mastering the Manufacturing Process: Key Factors and Their Impact

Kenaf and polypropylene fibers interwoven

A recent study investigated how several factors—number of plies, compression temperature, pressure, and time—influence the mechanical properties of kenaf-polypropylene composites produced using compression molding. The goal was to pinpoint the ideal conditions for maximizing tensile and flexural strength.

The study revealed that the interplay between these factors is complex. Here's a breakdown of how each element affects the final composite:

Number of Plies: Significantly affects flexural strength.
Temperature, Pressure, and Compression Time: These parameters interact with the number of plies to influence flexural strength, but have a less direct impact on tensile strength.
Tensile Strength: Influenced by degradation, fiber compaction, and the interaction between the fiber and matrix. The highest tensile strength (62.0 MPa) was achieved with 3 plies, at 210°C, 50 Bar, and a 3-minute compression time (low, high, high, low settings).
Flexural Strength: The highest flexural strength (80.3 MPa) was obtained with 3 plies, at 190°C, 50 Bar, and a 3-minute compression time (low, low, high, low settings).

In essence, achieving optimal composite strength is a balancing act. High temperatures can reduce matrix viscosity, improving fiber penetration, but can also lead to fiber degradation. Similarly, high pressure promotes fiber compaction, but excessive pressure combined with long compression times can lead to matrix embrittlement. The best results stem from carefully calibrated conditions that promote good fiber-matrix interaction without compromising material integrity.

The Future of Composites: Tailoring Materials for Performance and Sustainability

This research underscores the importance of carefully controlling manufacturing parameters to unlock the full potential of kenaf-polypropylene composites. While the study didn't find a single dominant factor for tensile strength, it highlighted the significant role of ply count and its interactions with temperature, pressure, and time in determining flexural strength.

By understanding these relationships, manufacturers can fine-tune their processes to create composites with specific properties, paving the way for more sustainable and high-performance materials in various applications.

Further research should focus on deeply understanding how each variable affects desirable qualities, such as strength. The goal is to create materials that not only perform well but also minimize environmental impact, driving innovation in the field of composite materials.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1088/1757-899x/223/1/012026, Alternate LINK

Title: Effects Of Number Of Ply, Compression Temperature, Pressure And Time On Mechanical Properties Of Prepreg Kenaf-Polypropilene Composites

Subject: General Medicine

Journal: IOP Conference Series: Materials Science and Engineering

Publisher: IOP Publishing

Authors: H S S Tomo, O Ujianto, R Rizal, Y Pratama

Published: 2017-07-01

Everything You Need To Know

What are Kenaf-polypropylene composites, and why are they important?

Kenaf-polypropylene composites are a type of composite material. They combine natural kenaf fibers with a polypropylene polymer matrix. This combination offers a sustainable alternative to traditional materials. This is important because it leads to the creation of stronger and more sustainable materials. The implication is that it can reduce energy consumption when used in various applications, such as automotive parts.

What is the 'prepreg method' in the context of these materials?

The 'prepreg method' is a technique used to manufacture kenaf-polypropylene composites. It involves preparing polymer sheets, arranging them with kenaf fibers in a sandwich structure, and then fusing them together under heat and pressure via compression molding. The significance of this is that it helps optimize the manufacturing process. This method allows for precise control over the materials' properties, which leads to superior performance of the composites.

What factors affect the mechanical properties of Kenaf-polypropylene composites?

Several factors influence the mechanical properties of kenaf-polypropylene composites. These include the number of plies, compression temperature, pressure, and compression time. The number of plies significantly affects flexural strength, while temperature, pressure, and compression time interact with the number of plies to influence flexural strength. These factors are crucial because they impact the tensile and flexural strength of the final product. It also allows manufacturers to tailor the material's properties for specific applications.

What influences the tensile strength of Kenaf-polypropylene composites?

Tensile strength is influenced by several factors. These include degradation, fiber compaction, and the interaction between the fiber and matrix within the kenaf-polypropylene composites. The highest tensile strength was achieved with 3 plies, at 210°C, 50 Bar, and a 3-minute compression time. The importance of understanding this lies in the fact that it helps to achieve the optimum balance. This means carefully calibrating conditions to promote good fiber-matrix interaction without compromising material integrity.

How is flexural strength related to the manufacturing process?

Flexural strength is the resistance of a material to bending. In kenaf-polypropylene composites, it is significantly influenced by the interplay of the number of plies, temperature, pressure, and compression time. The highest flexural strength was obtained with 3 plies, at 190°C, 50 Bar, and a 3-minute compression time. Understanding the interactions of these factors is essential because it helps to optimize the material's ability to resist bending forces. This also allows manufacturers to design composites suitable for applications requiring high resistance to bending.