Can There Ever Be a Plastic Detector or Is It Impossible?

While there isn't a specific sensor designed solely for detecting plastics, certain technologies like infrared spectroscopy or hyperspectral imaging can be used to identify and analyze materials including plastics based on their unique spectral signatures.

The Challenges of Detecting Plastics

The answer to whether a plastic detector can ever be built is not straightforward. Metal detectors work by detecting changes in electromagnetic fields caused by conductive materials, but plastics are not conductive, meaning they do not interfere with electromagnetic fields in the same way metals do. Therefore, a metallic detection principle cannot be applied to plastics.

Technological Perspectives

In science fiction, a poison detector is envisioned as highly advanced technology, often involving complex chemical functionality hidden in an apparently homogeneous material. Given the diversity of poisons and plastics, a similar approach might be needed. For detecting plastics in bulk, a homogeneous density of 0.7–1.6 grams/cm3 would be a key characteristic. Technologies like X-Ray Fluorescence (XRF) could be effective, though most modern XRF instruments struggle to reach low enough x-ray photon energies to identify specific elements like Carbon, Oxygen, Fluorine, and Nitrogen.

A cheap, portable detector capable of reaching into the ground to detect small bits of plastic in dirt seems unlikely. While chemical sensors might be useful, they would involve detecting the presence of specific elements or compounds on surfaces, rather than actively sensing plastic.

NMR Detection

The term 'plastic' is so broad and generic that building a 'Star Trek'-like plastic detector is highly questionable. However, there are possibilities within the realm of scientific detection. For instance, low-field Nuclear Magnetic Resonance (NMR) spectroscopy might be used to identify certain types of plastics. Fluorocarbon polymers, for example, should be readily detectable, though other plastics might also show detectable signals. However, an NMR expert would be needed to confirm the sensitivity and applicability of this approach. It is unlikely to be highly sensitive, but it might be sufficient to detect larger chunks of plastic.

Cost and Alternatives

Even though detecting plastic through direct means can be challenging, there are alternative approaches. For instance, adding a metal powder to the plastic manufacturing process can help in detection through metal detectors. However, this approach increases manufacturing costs and is not always feasible. Other additives might be considered, but again, cost plays a crucial role.

To combat the issue of plastic pollution, there is a growing emphasis on developing more biodegradable plastics. This is a promising avenue, but it requires significant research and development to make these alternatives cost-effective and widely adopted.

In conclusion, while a specific plastic detector might not be feasible in the near future, advancements in technology and materials science are increasingly focused on addressing the challenges of plastic identification and management.