Polymer safety barriers: PP vs. PVC—whats the difference?

PVC vs Polypropylene - Whats the difference?
If you found yourself reading this article, it’s probably because you’re looking for the technical differences between traditional polymer barriers and MPM polymer barriers.
Some manufacturers produce their barriers from a HDPE blend (high density polyethylene) but mostly we see barriers made from a polypropylene blend. MPM have bucked this trend by manufacturing their range of barriers from a PVC blend.
Both polymer types have distinctive advantages and disadvantages. The purpose of this article is to provide you, the reader, with a clear understanding, allowing you to make an informed decision about the most suitable material for your segregation project.
It should also be noted that we refer to the polymer as a base polymer because most manufacturers include additives to improve performance, such as UV absorbers, elastomers, and colorants.
Why should I care what Polymer my barrier is made from?
In truth, you have no control over what your barrier is made from. However, this factor could influence your decision if you're uncertain about which supplier to choose. An open honest technical assessment of each option should give you the confidence to make an executive decision.
How are polymers modified to improve performance?
If you’ve looked at data sheets and tried to understand what actual polymers are used for the various different types of pedestrian safety barriers you realise that in the main manufacturers don’t actually tell you what polymer their barriers are made out of.
Instead they give it a made up name such as Memaplex or Technopolymer. The reason for this is because the polymers on their own would likely not be suitable for their intended use. For example, a a barrier made from polypropylene without any modification should not be used outside as the UV light will degrade and break the polymer down. Similarly, a PVC barrier while very strong, without modification could be too brittle as an impact protection barrier instead both of these polymer types are modified to improve their performance.
Additives called elastomers are used to increase the toughness and impact resistance of PVC, This is very different from a plasticiser which makes PVC more malleable. Elastomers such as MBS turn PVC from a high stiffness but potentially brittle plastic, into a high flexibility, durable product suitable for absorbing impacts as can be seen with the MPM range.
There are two downsides to adding elastomers to PVC. Firstly and not perhaps very relevant for flexible industrial barriers but they reduce the optical clarity of PVC in other words. If you wanted your PVC bollard to be transparent, the MBS elastomer would cause a cloudiness within the polymer matrix. The other issue is it increases the cost of the product.
Polypropylene on the other hand, needs to be UV stabilised as it can start to degrade within months when exposed to UV lights. To stabilise polypropylene a number of UV absorbers, antioxidants and HALS (Hindered Amine light stabilisers). As with all additives for plastics there are often some downsides to each product and in the case of UV stabilisers in polypropylene, these can migrate to the surface and leach out overtime, this means that for external applications, we are improving the UV resistance to extend the life from several months to several years.
What is PVC?
PVC, or polyvinyl chloride, is one of the most versatile plastic materials available today. It’s widely recognized for its durability and resistance to environmental factors.
PVC is known for its toughness and stiffness and so can often be found in high pressure pipes, fenestration (doors and windows), and flooring. Its robust nature makes it an ideal choice for applications requiring long-term strength.
While durable and reliable, it's essential to consider how PVC interacts with different environments as well as any potential sustainability concerns related to its production and disposal processes.
What is polypropylene?
Polypropylene is a versatile thermoplastic polymer. It’s widely used in various applications, from packaging to textiles. This material has gained popularity due to its excellent durability and flexibility.
Polypropylene boasts a lightweight nature, making it easy to handle and transport. Its low-density properties enhance fuel efficiency in shipping industries.
The production process of polypropylene involves polymerizing propylene gas under controlled conditions. This results in a strong yet adaptable material suitable for both rigid and flexible designs.
With growing concerns about sustainability, many are exploring recycled polypropylene options. The ability to repurpose this plastic adds an eco-friendly dimension to its appeal while maintaining quality performance across different uses.
How does Polypropylene perform in UV light?
Polypropylene is a popular thermoplastic known for its versatility. However, it has a notable vulnerability: degradation under UV light exposure.
UV radiation can break down the polymer chains in polypropylene. This process weakens the material over time, leading to brittleness and loss of flexibility. The chemical bonds are disrupted, causing unsightly discoloration as well.
The degree of degradation varies based on factors like temperature and intensity of sunlight. In outdoor applications, this makes polypropylene less suitable unless modified or treated with stabilizers.
While it's cost-effective for many uses, prolonged exposure to UV light requires careful consideration regarding longevity and performance. Understanding these limitations is crucial when selecting materials for outdoor projects where sustainability and durability matter most.
Which is strongest?
When comparing the strength of PVC and polypropylene, factors like tensile strength and impact resistance come into play. PVC boasts impressive rigidity and can withstand significant pressure without deforming. This makes it ideal for structural applications.
PVC has a tensile strength of approx. 52MPa at 20C
On the other hand, polypropylene is also a tough polymer with a tensile strength of up around 25MPa at 20C. While it may not be as rigid as PVC, it tends to resist cracking under stress, which can be an advantage in dynamic environments. To compensate for this, manufacturers of PVC use a blend of elastomers to optimise the impact and shock resistance.
Which is the lowest cost?
When it comes to pricing, polypropylene often takes the lead. Its lower production costs make it an attractive choice for manufacturers and consumers alike. This affordability can be a significant factor in bulk purchases.
PVC, while still relatively inexpensive, tends to have slightly higher costs due to its manufacturing process. The added complexity of creating PVC products can push prices up compared to polypropylene options.
However, factors such as application and durability should also be considered. A cheaper upfront cost might not always translate into savings over time if maintenance or replacements are needed sooner with one material versus another.
Advantages of Polypropylene
Polypropylene stands out for its impressive flexibility. This characteristic allows it to adapt easily to various applications, from packaging materials to automotive components. Its ability to stretch without breaking makes it a favourite in industries where durability is key.
Another significant advantage is its lightweight nature. Polypropylene products are easy to handle and transport, cutting down on shipping costs and energy consumption during logistics.
Additionally, polypropylene boasts excellent chemical resistance. It can withstand harsh substances without degrading or losing integrity, making it ideal for containers and pipes used in the chemical industry.
The material also has good moisture resistance. Unlike some alternatives, it does not absorb water easily, helping prevent issues like mold growth or structural damage over time.
Finally, polypropylene is recyclable. This sustainability aspect appeals particularly to environmentally conscious consumers looking for responsible material choices in their daily lives.
Advantages of PVC
PVC, or polyvinyl chloride, brings a host of advantages to the table. One of its standout features is its exceptional strength. This material can withstand varying environmental conditions without significant wear and tear. That makes it ideal for construction and plumbing applications where durability is key.
PVC offers a smoother surface which makes cleaning easier, it is often used for cleanroom cladding as it allows easy washdown properties.
Another notable advantage is its excellent UV resistance. Unlike polypropylene, which degrades under sunlight exposure over time, PVC maintains its integrity outdoors. This quality extends the lifespan of products made from this material significantly.
Flexibility in design is another strong point for PVC. It can be moulded into various shapes and sizes easily, allowing manufacturers to create intricate designs that meet specific needs.
Sustainability may not be the first thing that comes to mind with plastics like PVC; however, advancements are being made in recycling processes for this versatile material. Many companies now focus on developing methods to recycle old PVC products effectively.
When weighing all these factors—strength, cost-effectiveness, UV resistance, flexibility—and considering sustainability efforts within the industry—it’s clear that both materials have their unique benefits based on intended use cases.
Which is the right barrier polymer for you?
Now that you know the difference between the two polymer types, this really boils down to whether you’re prepared to pay a premium for a PVC polymer barrier with its higher strength, UV performance and easy to clean properties or to choose a more budget friendly barrier based on Polypropylene. Still undecided? Download the buyers guide here.