Report of the IUPAC Working Party on Recycling of Polymers
The Macromolecular Division of the International Union
of Pure and Applied Chemistry (IUPAC) has a long-standing interest in
the recycling of polymers, as evidenced by the international symposium
it sponsored already in 1991 (Ref. 1). Because of the great societal
concern about this issue, the Macromolecular Division followed up this
action by formally establishing a Working Party
on Recycling of Polymers.
The Working Party was charged with reporting on the state of recycling
(Ref. 2) as applied to industrial polymers, and to make suitable recommendations.
The Working Party met on three occasions: in 1993 in Lisbon, Portugal;
in 1994 in Arlington, Virginia, USA; and in 1995 in Guilford, U.K.
In addition, it carried out extensive correspondence and was a principal
sponsor of the Microsymposium
on Recycling of Polymers that was held in Prague, Czech Republic,
in July 1997. The Working Party contributed a number of papers to this
volume, which are placed before those presented at the Microsymposium.
It also formulated certain recommendations, given below, which were
discussed at the Prague Microsymposium and adopted without dissent by
the participants.
This material will be published as part of the edition
of Macromolecular Symposia devoted to papers from the Prague Microsymposium
on Polymer Recycling 1997
> Published in Macromolecular
Symposia
135, 1-373 (1998)
The members of the Working Party who participated in at
least some of its activities are the following:
- Prof. Ann-Christine Albertsson
Royal Institute of Technology, Stockholm, Sweden
- Prof. Takashi Akehata
Science University of Tokyo, Tokyo, Japan
- Dr. Norbert M. Bikales, Chairman
National Science Foundation, Paris, France
- Dr. Johannes Brandrup
Verband Kunststofferzeugende Industrie, Frankfurt, Germany
- Dr. Michael M. Fisher
American Plastics Council, Washington, DC, USA
- Prof. Walter Heitz
Phillips-Universität Marburg, Marburg/Lahn, Germany
- Prof. James D. Idol
Rutgers University, Piscataway, NJ, USA
- Dr. Fred W. Mader
Association of the Plastics Manufacturers in Europe, Brussels, Belgium
- Prof. Robert H. Marchessault
McGill University, Montreal, PQ, Canada
- Prof. James H. O�Donnell (Deceased)
University of Queensland, Queensland, Australia
- Prof. Hans w. Schnecko
Hanau, Germany
- Dr. Rowan W. Truss
University of Queensland, Queensland, Australia
A number of other persons also contributed to the activities of the
Working Party; their names are given as authors or co-authors of the
papers published in this volume. Support from the International Union
of Pure and Applied Chemistry and the International Council of Scientific
Unions is gratefully acknowledged.
-
W.Heitz, symp. ed., "Recycling of Polymers,"
Macromol. Chem., Macromol. Symp. 57, 1992, 395 pp.
-
Official definitions of recycling apply in
various areas of the world, e.g., in the European Union. The term
is used here in the broad sense of reusing not only the material
content but also of recovering energy or chemical content of polymeric
materials that would otherwise be disposed of in wasteful ways,
e.g., in landfills.
Recommendations of the IUPAC Working Party on Recycling
of Polymers
The Working Party considers recycling and recovery of
polymers to be part of sustainable product use and development.
Sustainability as applied to recycling means consideration
of appropriate ecological, economic, and societal aspects.
Ecological aspects to be considered should encompass
- the conservation of resources
- the reduction of emissions
- the avoidance of hazardous substances
- the reduction of waste
Ecological, economic and societal aspects should be balanced.
The Working Party accepts mechanical and feedstock recycling
as materials recycling. Combustion for heat production with controlled
emissions is considered energy recovery, as shown in diagram A.
Mechanical recycling should be applied when the processing
energy put into the virgin product can be saved to a large extent through
reasonable technical efforts:
- the legal, medical and safety rules established for the use of plastics
and rubber are also observed for recyclates;
- the applicable (current and future) standards of plastics and rubber
are not deteriorated.
The ecological gain is the bigger, the smaller the technical
effort for recycling. Collection and sorting costs � although ecologically
rather unimportant � are economically very costly and have to be considered
as part of the overall recycling scheme.
Mechanical recycling leading to the substitution of virgin
plastic resins is the preferred route for waste that is rather homogeneous
in composition and largely uncontaminated. Because of this limitation,
it is very often restricted to production and processing scrap.
Mechanical recycling of mixed plastics, leading to substitutes
for wood or concrete products, cannot by itself solve the large problem
of post-consumer waste, and may be ecologically misguided as shown by
recent life-cycle analyses.
The Working Party recommends that heterogeneous, mixed
and contaminated waste should instead be treated by the methods of feedstock
recycling or energy recovery as outlined in diagram B.
Recovery of Plastics Waste The Options
RECOMMENDED RECOVERY OPTIONS FOR DIFFERENT TYPES OF PLASTICS
WASTE
Type of Plastic Waste
|
Mechanical
Recycling
|
Feedstock Recycling
|
Energy Recovery
|
Sorted, single Type Plastics
|
++
|
+
|
+
|
Mixed Plastics
|
+
|
++
|
++ (Plastics derived fuel)
|
Mixed Plastics & Paper etc.
|
-
|
-
|
++ (Refuse derived fuel)
|
Plastics in municipal solid Waste
|
-
|
-
|
++ (Municipal solid waste combustion)
|
+ = suitable/ ++ = preferred
Costs increase as more collection and separation is required
for the recovery process
So-called cradle-to-grace approaches for products should
be used for finding the most sustainable route for fulfilling human
needs. Detailed life-cycle analysis seems to be a proper tool for evaluation.
The Working Party considers that all recycling of plastics
and rubber should have an ecological or economic goal. Without such
justification, it should not be done simply for its own sake.
The Working Party recalls that scientific and technological
advances have produced a large variety of tailor-made plastics and rubber
products that have been manufactured in order to satisfy a broad range
of human needs, often in a sustainable way. This important and often
critical societal contribution of polymers must be considered in a balanced
way.
The Working Party recalls that scientific and technological
advances have produced a large variety of tailor-made plastics and rubber
products that have been manufactured in order to satisfy a broad range
of human needs, often in a sustainable way. This important and often
critical societal contribution of polymers must be considered in a balanced
way.
The Working Party recommends that IUPAC continue to promote
-
research which leads towards the development of polymers
and composite materials within a framework of sustainability, as
well as
-
technologies and standards for polymer recycling an
recovery
-
the establishment of a polymer recycling network that
would permit easy exchange of information and act as an information
database.
These recommendations were presented by the Working Party
at the IUPAC Microsymposium on Recycling of Polymers in Prague in July
1997 and were unanimously approved.
Ecological, economical and social aspects should be balanced.
The Working Party accepts mechanical and feedstock recycling
as material recycling. combustion for heat production with controlled
emissions is considered as energy recovery as shown in diagram A.