A plastic bag degrading into natural elements.

The Future of Plastic Bags: Are Biodegradable Options Really the Answer?

Nico Varela in Climate & Environment June 2025 • 4 min read.

"Digging into the science behind polyethylene blends and how they might help solve our plastic waste problem."

Plastic has become an indispensable material in our daily lives, largely replacing glass, paper, and metals due to its affordability, durability, and lightweight nature. This widespread use, however, has led to a global crisis: the staggering amount of plastic waste, especially from packaging. When recycling isn't viable, plastics often end up as persistent litter, prompting the search for biodegradable alternatives.

The focus has shifted towards biodegradable polymers, targeting products where their properties offer a tangible advantage and resonate with consumers. For a plastic to be truly environmentally friendly, it needs to break down mechanically, reducing the molecular weight of its components to a point where they can be easily consumed by microbes.

Scientists and manufacturers are exploring innovative solutions like incorporating light-sensitive additives or copolymers into synthetic polymers, which weaken the bonds in the presence of ultraviolet radiation. One such product, PolyStarch N, combines cornstarch with LLDPE (linear low-density polyethylene) to trigger both photodegradation and thermal-oxidative breakdown. But how effective are these solutions in the real world?

How Do Polyethylene Blends Degrade? A Closer Look

A plastic bag degrading into natural elements.

A study published in the "Journal of Chemical Engineering" investigated the degradation of polymer blends designed for environmentally degradable plastic bags. Researchers Ruhul Amin M., Basel F. Abu-Sharkh, and Mamdouh Al-Harthi examined how adding photodegradable additives to polyethylene films affects their breakdown under natural weathering conditions in Saudi Arabia.

The team exposed these films to outdoor conditions in Dhahran and then meticulously analyzed their fractured surfaces using Scanning Electron Microscopy (SEM). This allowed them to observe the morphological changes and assess the effectiveness of different additives in promoting degradation.

Additives Tested: The study compared different additives, with PDQ-H showing the most promise in accelerating degradation in the harsh desert environment.
Environmental Conditions: Films were exposed to the intense sunlight and heat of Dhahran, Saudi Arabia, mimicking real-world conditions.
Analysis Method: Scanning Electron Microscopy was used to examine the fractured surfaces of the polymer blends, providing detailed visual evidence of degradation.

The SEM images revealed that degradation begins at specific points and gradually expands, eventually covering the entire film. Initially, the blends showed no visible cracks, but as exposure time increased, cracks began to appear, indicating the breakdown of the material. After a certain period, the degradation accelerated rapidly, with large cracks forming across the surface. This process is attributed to the degradation of starch components and the oxidation of LDPE (low-density polyethylene) in the amorphous regions.

The Future is Degradable

While challenges remain, the research indicates that certain additives, like PDQ-H, can significantly enhance the degradation of polyethylene films in harsh environments. The study concluded that under the conditions tested, the plastic samples were almost completely degraded within eight to nine months. Further research and development in this field could pave the way for more effective and sustainable plastic alternatives.

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: 10.3329/jce.v27i1.15847, Alternate LINK

Title: Surface Microstructure Study Of Polyethylene Blends For Developing Environmental Degradable Plastic Bags

Subject: General Medicine

Journal: Journal of Chemical Engineering

Publisher: Bangladesh Journals Online (JOL)

Authors: M Amin Ruhul, Basel F Abu-Sharkh, Mamdouh Al-Harthi

Published: 2013-07-26

Everything You Need To Know

What are the key challenges in developing truly biodegradable plastic bags?

The primary challenge lies in creating plastics that degrade effectively in various real-world environments. While some blends, like those incorporating cornstarch with LLDPE (linear low-density polyethylene), show promise through photodegradation and thermal-oxidative breakdown, their effectiveness varies. A significant hurdle is ensuring these materials break down completely into components that can be consumed by microbes, preventing persistent litter. The study highlighted the importance of environmental conditions, such as intense sunlight and heat, in accelerating degradation, suggesting that the success of biodegradable plastics is highly dependent on the specific conditions they are exposed to. More research and development is needed to overcome these challenges and create sustainable plastic alternatives.

How does Scanning Electron Microscopy (SEM) help in understanding the degradation of plastic blends?

Scanning Electron Microscopy (SEM) plays a crucial role in visualizing the degradation process of polyethylene blends. By examining the fractured surfaces of the plastic films, SEM provides detailed visual evidence of how the material breaks down over time. Researchers can observe morphological changes, such as the formation and expansion of cracks, which indicate the breakdown of the material. In the study, SEM images revealed that degradation begins at specific points and gradually covers the entire film, providing insights into the effectiveness of different additives in promoting degradation. This method allows scientists to assess the degradation process in detail, helping them understand how different components and environmental factors influence the breakdown of plastic blends.

What specific additives and conditions were tested in the study on polyethylene film degradation?

The study investigated the degradation of polyethylene films under real-world conditions in Dhahran, Saudi Arabia, focusing on the effects of different additives. The key additives tested included PDQ-H, which demonstrated the most promising results in accelerating degradation in the harsh desert environment. Films were exposed to intense sunlight and heat to mimic real-world weathering. The study analyzed the fractured surfaces using Scanning Electron Microscopy (SEM), which provided visual evidence of the degradation process. The environmental conditions, particularly the intense sunlight and high temperatures, were crucial in promoting the breakdown of the plastic samples, with some additives leading to almost complete degradation within eight to nine months under these specific conditions.

What are the implications of using polyethylene blends with additives like PDQ-H in plastic bags?

The use of polyethylene blends with additives like PDQ-H in plastic bags holds significant implications for reducing plastic waste. The study showed that under specific conditions, these blends can degrade significantly faster than traditional plastics, potentially mitigating the environmental impact of plastic waste. This faster degradation is achieved through the breakdown of starch components and the oxidation of LDPE (low-density polyethylene) in the amorphous regions. However, the effectiveness of these blends is highly dependent on the environmental conditions and the type of additive used. While PDQ-H showed promising results, it’s essential to understand that these blends are not a universal solution, and their performance can vary. Further research and development are needed to create more effective and sustainable plastic alternatives that are truly environmentally friendly.

How do different polyethylene components, such as LLDPE and LDPE, contribute to the overall degradation process in plastic blends?

In the context of biodegradable plastic bags, different polyethylene components play distinct roles in the degradation process. LLDPE (linear low-density polyethylene) is often combined with components like cornstarch, acting as a base material. LDPE (low-density polyethylene), on the other hand, experiences oxidation in its amorphous regions, contributing to the breakdown. The addition of additives like PDQ-H, can accelerate this process. The study highlights that the interplay between these components, the additives, and environmental factors determines the rate and extent of degradation. The starch components trigger photodegradation and thermal-oxidative breakdown. The effectiveness of these blends is highly dependent on the specific environmental conditions, and the type of additive used. While PDQ-H showed promising results, it’s essential to understand that these blends are not a universal solution, and their performance can vary.