Page 21 - 《CHINA RUBBER/PLASTICS INTELLIGENT MANUFACTURING AND ENV.PROTECTION》2018.5

Viewpoint P 16

Environmental ageing elastomers-the duality of crosslinking and chain scissions
Most of polymers present limited resistance to ageing including the ageings involved by
0
environmental stress(heat,light,etc).The main reason is their ability to generate macroalkyl radicals(P )
derived themselves from the presence of impurities,in particular those coming from their processing at
relatively hign temperature(peroxides of hydroperoxides for example).
As it can be seen on the following scheme the main mechanism involves a fast oxidation of
0
macrealkyl radicals resulting in the formation of peroxo radicals(POO ) and various functional
polargroups easily revealed by FTIR spectroscopy(hydro peroxides,alcohols,ketones,carboxylic
acids).The presence of methyl(chain end) ketons,carboxylic acids and some volatile compounds
(methanol,CO 2 ,H 2 O)characterises chain scissions which can also be pointed out by molecular weight
or viscosity measurement .In thecase of photo ageing, additional chain scissions are produced by the
photochemical decomposition of ketones via Norrish reactions (Norrish type i produce essentially
shorter chains ketones,aldehydes and carboxylic acids as Norrish type II produce methyl(chain end)
ketones and viny(end groups) or other unsaturated groups and shoter ketones).

Plastic machinery is listed in the USTR suggested tax increase Indonesia publicly questioned the export volume of major rubber
list,What is CPMLA'spoint of view? ............................................38 producing countries ....................................................................48
Cooper Tire awarded the industry quality leading enterprise Exxon Mobil launched new aiqifeng high-end polypropylene ....48
and integritydemonstration enterprise ........................................ 39 EU imposes anti-dumping duties on Chinese truck and bus tires ........49
Hainan has underwritten the first targeted poverty alleviation Four steel cord manufacturers protest U.S. tariffs ......................50
income insurance of natural rubber industry in China ................ 39 Why does Clariant invest in plastic innovation? Sustainable
China rubber museum is preparing to be built ........................... 40 development is the key...............................................................50

Overseas news U.S. lowers China's tire tariff rate ...............................................51
The world's first marine plastics cleaner will be commissioned and
After the combination of Michelin and Sumitomo,Goodyear
try to deal withPacific rubbish debris .......................................... 52
established a jointventure with bridgestone ...............................41
British men invented "non-plastic water bottles" to degrade in only
Abstracts Column
three weeks ................................................................................42 Application of graphene/rubber masterbatch insemi-steel radial
Brakesem's UTEC Expands Global UHMWPE Innovation and tires.............................................................................................53
Customer Coverage ...................................................................43 Effect of rubber asphalt performance on roadperformance of
Total cooperated with Polystyvert to recycle post-consumer rubber asphalt mixture............................................................... 56
polystyrene .................................................................................43

Dow focuses on product innovation to help the sustainable Patent abstract
development of plastics industry ................................................ 44 Plastic pipe .................................................................................57
Multi-cavity de-threading mechanism and mould controlled by
Global rubber consumption has grown steadily .........................46
single screw............................................................................... 60
The market outlook for automotive modified plastics is expected to
exceed 6.4 million tons in 2022 ..................................................47 General Konowlodge for R&P

Britain's 42 plastic products related enterprises signed the British Coordination system of oil resistant rubber ............................... 61
Plastics Agreement for the first time ...........................................47