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 options
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.
Ravi Raghavan
Chemical Weekly Issue date: 28th August 2018
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