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Research and Development of
Degradable Plastics in China 唐赛珍
(TANG Saizhen) Research Society for Degradable Plastics, Chinese Plastics Engineering Association, Beijing 100088 1.
Production and
Consumption of plastics industry in China Plastic
industry is both a product processing industry and a material industry. With the
development of petrochemical industry and social demand, plastics industry is
developing very fast. During the past 10 years (1990-1999), the average annual
growth rate is 15.32% in the production of resins, and 18.95% in the
manufacture products.（Fig.1） Fig.1 Development of
plastics production and consumption for synthesis resins and plastics products
in china [1] [5]
The
total volume of synthesis resins reached 6756kt ,
and 16625kt for manufacture plastics products in 1998
. China ranged among the five biggest plastics production countries in
that year, its out put of synthesis resins was only behind United States, Japan,
Germany and Korea at five in the world, plastics processing products are only
second to the United States.（Fig.
2） Fig.2 Ten largest
plastics producing countries
Plastics
consumption increases rapidly with plastics production in China. The application
areas for plastics expand further. Statistic plastics consumption was 14,940
kilo tons and plastics processing products was 14,276kt in 1998. Plastics
materials and products have been used as an important industrial raw materials
and consumption materials widely used in various industries, agriculture,
packaging and hi-tech areas. It has become one of the four pillar materials
including steel, wood, and cerements. It has played an increasing important role
in various national economies. （Fig.
3） Fig.3 The market
distribution of plastics products in china （1998）
2.
China’s present condition of disposable
plastics products waste and administering countermeasures for it [6] Although
plastics have a lot of advantages, they are not easily environmentally
degradable, thus causing a lot of problems. Especially disposable packaging
plastics and daily plastics, they go with the household plastics to the city
solid waste treatment system. Many cities in China only dispose the waste on the
ground or slightly bury the waste under the surface although large cities like
Beijing, Shanghai and Shenzhen do have better hygiene treatment and modern
treatment facilities, when wind comes, the light plastics bags and film will be
flying in the air, plus weak environmental consciousness, plastics waste become
an disturbances on the streets, in railways, in rives and lakes and tourism
sites, causing negative efforts on living environments and ecological systems.
Termed “white pollution” in China. According
to the statistics by related departments, The plastics for packing purposes have
about 4000kt on 1998, in which disposable plastics package that recycled hardly
was 30%, it means that the production for plastics package waste is about 1200kt
at that year in china; plastics agriculture mulching film waste is 400kt;
disposable daily and medical plastics waste is 400kt. Therefore production for
disposable plastics products waste
are 2000kt （Fig.
4）. Fig.4
The composition of disposable plastics products waste in china According
to result of investigations into Beijing, Shanghai & Tianjin, the proportion
of plastics waste at the MSW is 3～7%（weight）and
is 10～20%（volume）（Fig.
5、Fig6）.
For this
status, Chinese government pays great attenation to the environmental pollution
caused by plastics products waste, has studying administering countermeasures
Vigorously and applying a means for administration, science & technique and
economics to comprehensively govern. In the way of management On
the PS form lunch boxes and over thin plastics film and bags, a par cities of
china, such as Beijing, Shanghai, Tianjin, Guangzhou, Xiamen, Hangzhou, etc have
been promulgated orders and regulations, principal points of which are control
source, strength recycle, gradually prohibit and encourage substitute. In the way of technique The
governing for plastics products waste is a systematic engineering at society. In
the way of technique, important means is progress depended on science and
technique, it includes resource saving, resource regenerative application and
making it harmless.
3.
The situation of research and development of degradable
plastics in china The progress of degradable plastics in china
·The
study of photo-degradable plastics in china has started from the middle of
1970s. ·The
study of starch-filleting Biodegradable Plastics has started on 1980s by a few
units. ·The
environmentally degradable plastics getting on with studies and quickly
development on 1990s.
The variety of degradable plastics researched in china photo-degradable
, photo/ Biodegradable , photo/ calcium carbonate degradable , environmental
degradable , Biodegradable & Bio-destructible plastics（high－filled
starch）,
high－filled
environmentally friendly material etc .
·The
item of 《research
for photo/ Biodegradable & environmentally degradable plastics mulching film》
have been figured into national key task in
eighth five－year
plan and ninth five－year
plan. ·The
item of 《denatured
starch and it's Biodegradable functional plastics master batch & products》
has been figured into national program ,
which will become item of industry exemplary engineering ;
·The
Biodegradable plastics such as PHBV, PHAs, PCL… etc has figured into national
key task in ninth five－year
plan, and now it is pilot-plant test. Of
late years, research and development of China’s degradable plastics have made
great progress, especially on the environmentally degradable plastics and the
starch-base Biodegradable plastics. China’s progress on the research of
degradable plastics catches the world step, the technique is close to, or
even matches the advanced world level, exclusive of the Biodegradable and
synthetic photodegradable technique. The present status of degradable plastics in
china:
·Production
companies near 100 ; ·Twin-screw
extrude line over 100 ; ·Productive
capacity about 100kt ; ·Production
near 30kt ; ·Applications
field package , agriculture , daily , medical , staple products；
At
present, the agricultural mulching film application in China is still under test
du to the problem of precise timing, and the degradable plastics for disposable
packaging and daily products are just orderly going to markets, at the same time
apart of degradable master batch and manufacture products are export to abroad
markets.
At
the moment, among this degradable plastics products, the typical technique and
products are the denaturation starch technique and “starate” starch-base
Biodegradable series products of TIANJIN
DAWNHALO APPLIANCES CO.,LTD, which processes oneself knowledge property . the
content of starch in packaging film is over 50% , and in seeding pots and
injection module reach 60～80%.
This means that the products not only has well Biodegradable property, but also
may be saving finite petroleum resource, decreasing plastics waste as well as
profiting to lessen governing for MSW. Tab.2
Principal producing corporation of degradable
plastics in china
The activity of DPRS
The
degradable plastics research society （DPRS）of
the china plastics engineering association was founded on July 1993 . In recent
years getting on following research and works: ·Follow
the track investigation of the development for degradable plastics at home and
abroad.
·Organization
the conference of technique and information exchange for degradable plastics at
home and abroad. On 1992～1996
following professors and specialists has been attend the workshop committee of
degradable plastics in china. ·Professor
S.Mc.Carthy of America on 1992; ·Professor
Gerald Scott of Britain on 1993; ·Specialists
Dan Gilead of Israel on 1993; ·Director
Graham Chapmen of America on 1994; ·Professor
Riley N.Kinman of America on 1994; ·Professor
F.P.Lamantia of Italy on 1995; ·Director
Ake Rosen of Swedish on 1995; ·Specialists
Dai Wu Yi Ren of japan on 1996; ·Director
Elmar S.Chroter of German on 1996. ·Publication
degradable plastics newsletter. ·Research
the methods of test－evaluation
and standard for degradable property. ·Test
of soil filled and covered up. ·Test
of garbage heaped and covered up. ·Research
of the standards and the mark for degradable plastics. the standards has been issued in china
4.
Some problems and consideration on China’s process of degradable plastics
marketing To
ease the environmental pollution caused by disposable plastics waste, China’s
marketing process of degradable plastics is speeding up. A lot of experience is
accumulated during the application process in recent years; however,
obstructions and problems are still remained.
·A
unified definition needs to be decided. There is still much arguing about
degradable plastics and its function in resource environmental protection caused
by lacking unified understanding and precise evaluation. ·The
unified evaluating way, distinguish marks and products testing standard need to
be established systematically. Now the technical market and products market are
rather in confusion. ·Degradable
plastics technique itself needs to be further promoted and perfected.
Such as the reasonable formula, the precise timing, the plastics
degrading quickly and completely, and the recycle technique for leftovers. ·The
price leverage plays a role in market economy. Now the rather high price is hard
to come into the market. The expensive price of the complete Biodegradable
plastics is of course the main obstruction to come into the market. After
10 years research, development and application experience, for accelerate the
market process, must have a proper understanding, multiple cooperation and a
correct guide. The most important of all is to reach a proper understanding and
precise evaluation about degradable plastics and its function in resource
environmental protection. The followings are my personal views: Reach a proper understanding on degradable plastics
After
following application research for many years and based on China’s national
condition, to give a comprehensive consideration from practical, degradable,
safety and economical points, degradable plastics must reach the following
demands: · Practicality. It should have the same or similar applicable and healthy function with the common plastics under same category. · Degradability. After completing its using function, it should degrade quickly to bits and scraps, which are harmless or easily absorbed by environment in natural condition and will return to nature at last. ·
Safety. The remnant produced in degradable process and after it should be
harmless or has no potential harm to environment. ·
Economical consideration. It should have the same price level with common
plastics under same category or a little higher price than that.
Reasonable
orientation of purpose for degradable plastics In
our life, there are lots of disposable plastics products such as consumer
packing bags（film）,
compost bag, lunch boxes, seeding bowls, which are dirty and messy and hard to
collect, have a large quantity of waste, and have a little economic returns even
being collected. Therefore degradable plastics are preferable used for
disposable products. Implying by the long-term laboratory test, land filling,
compost, and field covering, etc, degradable plastics researched and developed
currently in china can change shape, reduce physical properties, decline
molecule weight, transform chemical structure, Biodegradable under a certain
condition. After a certain period. The result proves these products not physical
reaction also chemical reaction and fulfill process of deterioration, decay,
destructing, degrading. With such reactions the waste can break into innocuous
pieces and result in the less of volume and mass, hence less environmental
pollution and can be compatible with nature finally. Evaluate the applicable results of degradable plastics in an objective manner
According
to the following experiments on covering with degradable plastics mulching film
and the researches on soil chemical pollution and physical pollution led by Soil
and Fertilizer Institute of China’s Academy of Agricultural Science in recent
10 years, that is known: ·Degradable
plastics covering has no clear effect on N, P, and K, nor did it have heavy
metal （Cr，Cd）
pollution
to soil or accumulation of microelement such as Co，Cu，Ni
and Mo. ·As
long as the waste plastics mulching film break into cracks smaller than 16cm2,
the accumulated remnants in 20 years have a little possibility to have effect on
soil capacity, proportion, soil water activity, soil holes etc . They have no
harm effect on crops’ growing either.
·Based
on this understanding, we need not make excessive demands that degradable
plastics should degrade into CO2 and H2O in a short time.
As time passing, at last it will return to nature, only the degradable cycle is
longer than natural material, but still greatly shorter than common plastics.
This attitude is beneficial both to marketing process and environmental
protection. Using
products life cycle analysis (LCA) to evaluate environmental protection
adaptability of degradable plastics Evaluate
the relation between plastics and environment just from the popular point
whether its waste are easy to dispose, That is unreasonable to evaluate any
material’s environmental protection adaptability, we must consider various
elements such as the reasonable usage of resources, energy conservation and easy
disposition after usage. That is to say, only using the products life cycle
analysis to evaluate, can its environmental protection adaptability be actually
reflected.
Speed
up to research disposing technique combining Biodegradable plastics and compost Compost
is beneficial to the application of Biodegradable plastics. As practical
application shows, degradable plastics products with high starch content are
easy to compost. According to
experience from foreign countries, garbage bags must be made of Biodegradable
plastics for compost. Combining Biodegradable plastics and compost together is a
good way for resource recycle and protecting environmental pollution caused by
disposable plastics waste. Promote
the research for formulating the testing evaluation standard of degradability
and safety In
order to promote the research, development and application process, the testing
evaluation standard on degradability and safety must be researched and
formulated soon.
Deepen understanding of the Biodegradability of polyethylene According
to the research of domestic and foreign experts, especially Japanese Professor
Dai Wu Yi Ren, We tentatively ascertain that PE is Biodegradable and its
biological degradability can be enhanced when added into metamorphic starch and
concerning additive. Its degradable mechanism is also tentatively ascertained.
All of above research are useful for research, development, popularize and
application of degradable plastics. 5. The prospects of the degradable plastics market in China China is a
developing national with a population near 1.3 billion. In recent years , the
average annual growth rate of GNP was 7～8%,
18.95% was in China’s plastics industry. The consumption of
disposable plastics products is keeping increasing with people’s improving
living standard. Degradable plastics is preferable, compared with
disposable plastics products which are dirty and messy and hard to collect, have
a large quantity of waste, easily disperse, and have a little economic returns
even being collected and recovered. According to the forecast by related department. The demand of china's plastics packaging material will be 5000kt, at the beginning of the 21st century, in which disposable plastics package that recycled hardly is 30%, it means that the production for plastics package waste will be 1500kt. The covering area of mulching film is 500000kmu in china, and the present the covering area only reached 30%, and plus that the demand of the seeding pots and the film maintained raw fresh for agricultural products , it will be 1000kt , The demand of daily and medical which are recycling hardly and not fitting to recycle will be 1000kt . Same up production of disposable plastics products waste were be 3500kt. Therefore, China's degradable plastics has a great national market potential. As
a result of hi-tech and a product for environmental protection, degradable
plastics has been a concerning focus of research and development of the world.
Not only its development enlarges the plastics function area, but also, to a
certain degree, alleviates the deterioration of environment. Being a supplement
to the exhausting petroleum resource, it reveals the power and the prospect of
biological technique and alloying technique in plastics material area from its
synthetic technique. In a word, the research, development and application of
degradable plastics has an important meaning for environmental protection of the
earth, for getting an inexhaustible regenerated resource, as well as for
academic research of synthesizing functional high polymer. Being still in the
ascendant, the degradable plastics technique shoulders heavy responsibility and
has a long way to go. Degradable plastics is due to have a better tomorrow. Main reference material: ·YangHuiDi，《China Plastics》2000，14（6）：1 ·プラスチシヶスヱ—ジ
1999，45（12）.140 ·《China
Consumption News Paper》1995.10.2 ·LiaoZhengPin，《Plastics》
2000（6），1 ·GuanZhaoJi，《China Plastics》2000，13（6）：1 ·TangSaiZhen，《China Synthetic Resin And Plastics》7（2）2000.1 ·TangSaiZhen，《China Plastics & Rubber Journal》2000，19（6）140
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