Plastics industry: Proactive approaches to tackle waste issue
The plastics industry has been in the news recently, mostly for the wrong reasons. The issue of plastics waste has come centrestage in developed and developing countries including here in India. Several states, Maharashtra included, have moved to ban single use plastics, and there is loose talk of banning all types of plastics as well, though this will be well nigh impossible given the diversity of uses to which these ubiquitous materials are now put to.
The issue was also a point of discussion at the recently concluded Asian Petrochemical Industry Conference held in Kuala Lumpur. The conference traditionally touches on market dynamics – demand, supply, pricing etc. – and this year’s emphasis on the environmental challenges faced by the industry was a departure from the past and reveals the concerns of the petrochemical industry, which makes all of the basic resins that are then compounded and processed to make plastics goods.
Changed public perceptions
There is no denying that the public perception of plastics has changed as the petrochemical industry expanded greatly in size. When first introduced in the early 1950s, plastics were considered wonder materials that, simply put, made life better due convenience and tremendous utility. By the turn of the century plastics came to be indispensible to modern living and it was said that the consumption of polypropylene – the second largest thermoplastic – could be used as a proxy for the GDP of a nation; the higher the consumption per capita, the more prosperous the country.
The produce-use-dispose model that quickly came to dominate, best exemplified by the packaging industry, first came to be questioned by environmentalists about two decades ago, but in the last few years the movement against plastics has gathered momentum and forced governments to act – often with outright bans and restrictions. This is where the plastics industry is today and the question that needs to be asked is whether going forward it will lead in addressing the issue or be dragged unwillingly into a future it does not want?
What are some things that the industry can do in order to take the lead in the transformation that is coming? The answer lies partly in an old mantra – reduce, reuse and recycle. In addition, the industry needs to embrace biodegradable polymers, and wherever possible use bio-based polymers.
Reduce and reuse
A good way to reduce consumption of single use plastics is to consider use of returnable & reusable containers. There was a time when milk in Mumbai was delivered in glass bottles that were returned, cleaned and reused. This author remembers making annual school picnics to the Aarey milk factory in what was then the outskirts of Mumbai (Goregaon) to see a milk bottling plant. The process of washing and drying the bottles in long conveyor belts, using copious quantities of hot water, was an impression clear to this day in the mind. Packaging milk in glass bottles may not be practical today, given the much larger size of the market and the efficiencies that plastics bring (most importantly minimising contamination). This has been recognised by even the Maharashtra government, which in its recent ban on single use plastics, has wisely chosen to exempt milk packaging, nearly all of which is made from LDPE.
But there are several other commodities that can be packed in reusable containers or even delivered without packaging but implementing such an approach will involve engaging all stakeholders in the value chain. Technology can play a role here – as has been shown in some middle income countries wherein food is being delivered from the farm to the ultimate consumer using digital platforms (apps). Some large home and personal care companies, to cite another example, are piloting programmes wherein they do away with packaging entirely and offer ‘open’ products at special dispensing stations. These are as yet small initiatives and will need to address several obvious issues, the most important of which is preserving the integrity of the product and ensuring it remains safe and useful till the point of consumption.
Replace multi-layer films with homogeneous films
Given that multi-layer packaging films contain layer upon layer of diverse materials – a range of polymers, paper and metals – their recyclability has always been tricky. These layers are needed to ensure performance, especially protection of the contents (such as foods) from the elements (UV radiation, oxygen). One option is to replace the diverse materials with homopolymers, i.e. polymer belonging to one chemical class, but doing so with no deterioration in performance is a huge technical challenge that can be overcome only with a high level of innovation. One approach being taken is to tailor polymer structure at the nano-scale, and so enable the polymer to mimic the different layers that a heterogeneous film has.
Rational design and proper labelling
An easier task will be to rethink packaging design a priori and avoid the tendency to over-design to cater to far-fetched exigencies. Why go for a complex, multi-layer packaging that includes polyester, ethylene vinyl alcohol copolymer, paper and aluminium, unless the product absolutely demands it? Design must be done while keeping end-of-life treatment as an important factor, not an after-thought.
It is also important to ensure that labelling on packaging is scientifically accurate to ensure that disparate polymers are not mixed together and taken to recycling. One recent controversy here concerns the labelling of PET and glycol-modified PET (commonly known as PETG) with the number 1 in the triangle, even though the two have different melting points that will pose challenges in recycling. California has ruled that only classical PET can be labelled with the number 1, and PETG be clubbed with other polymers with the number 7.
Go biodegradable where possible
Biodegradable polymers are an option to make food packaging, dishes, cutlery etc., as they will degrade in landfill sites or can be composted (the latter, of course, requires collection and composting infrastructure). Polymers such as polylactic acid and poybutylene succinate can be adopted for such uses, but the problem is as much about costs as changing well-entrenched consumer behaviour.
More efforts are also needed to make existing plastics more biodegradable, possibly through the use of additives that accelerate breakdown of the polymer chains at the end of the product’s useful life. Some success has been reported in this area, but expect to see more innovation here.
There is a controversy regarding the use of oxo-degradable plastics, i.e. plastics that fragment under certain environmental concerns. A study by the European Commission has concluded that this approach may actually be counterproductive as it worsens the problem of ocean pollution, as the small plastic pieces make the way into drains, rivers and eventually the seas.
Exotic solutions, such as using bacteria to degrade plastic wastes, are also being reported in laboratories. Tailored bacteria can ‘eat’ plastics such as PET and depolymerise it back to the monomers for reuse. But a lot of work still remains to be done before these smart ideas transition to a commercial reality that can work at the scale at which waste is being generated.
None of these solutions outlined above will alone solve the problem of plastic waste, but together they can make an impact. Governments must recognise and support research and market initiatives to mitigate the environmental impact of plastic materials. The industry, on its part, must step up ownership of the issue, and highlight proactively the many approaches it and its partners are taking. Only then will it have a chance of winning the approval of citizens – something the industry took for granted for nearly three quarters of a century.
Disclaimer: Echemi reserves the right of final explanation and revision for all the information.