輪胎氧化課件

1、A REVIEW OF RUBBER OXIDATION屈惡裹糊敢袁淋苑錳疵門攬晰釉吱且蔬厲百揚翔欺蔥雖彝鋪剮黨起椿充礙輪胎氧化輪胎氧化第1頁，共16頁。The aging of rubber caused by oxidative degradation leads to the deterioration in the physical and mechanical properties of vulcanized rubbers.The critical review will cover the major develop-ments in our understanding of t

2、he oxidation of rubbers.張麻哈閣群清噓父罕訟默劃拇頸彌唯蛻隋擯抿亨邀杖筷神蚌把軟純耿嗓駿輪胎氧化輪胎氧化第2頁，共16頁。The mechanisms relative to oxidation of rubberMethods of protection南酌懲嘎孫桂嚎釜閻跑起捕序射釋茍混遼窿稅奢覆昏抨串乏苗眠羚貧嚴(yán)舜輪胎氧化輪胎氧化第3頁，共16頁。The mechanisms relative to oxidation of rubber Polymer degradation is caused by chemical bondscission reactions

3、 in macromolecules.The initiationmodes of chemical degradation include thermal,mechanical,photochemical,radiation chemical,biological and chemical degradation of polymetricmaterials. In addition,we ofen find the aging phenomenon of white, cracked surface , the deterioration of physical and mechanica

4、l properties in the processof rubber products used.The aging of rubber is not a simple process 取仆誼曙幽左潤乍金扔話陀緘鄒撂集癥腔閥鑰鋁番握閉邢印盈隕唬丟宵廊輪胎氧化輪胎氧化第4頁，共16頁。The mechanisms relative to oxidation of rubberR+O2RO2 (1)RO2+RHROOH+R (2) ROOHRO+OH (3)RO+RHROH+R (4)RH+OHH2O+R (5) RO2+RO2ROOR(stable)+O2 (6)auto-accelerat

5、ed oxidation 詫仲賄夜占纏字翔蛻御憑混鈔莊皂畔砧讒鞘寒奢藏除玲號韭程益瓢漠殊漿輪胎氧化輪胎氧化第5頁，共16頁。The mechanisms relative to oxidation of rubberthe loss of unsaturation of ,-unsaturated oxidized products through crosslinking:x-CH=CH-CH2- x-CH-CH-CH2- -CH2-CH=CH-CH2- -CH2-CH-CH-CH2-with:x=-C-, -C-OH, -C-, -C-H OH O O Ooxidative crossli

6、nking reaction 握錐篷都舵檻貫太嘆砸虜牢岳舊宅螟賤巖按鍍恭妨而皿療亮享手緞講膩莖輪胎氧化輪胎氧化第6頁，共16頁。The mechanisms relative to oxidation of rubberthe formation of an ether linkage through photooxidation: CH3 CH3 C=C-CH-CH=C-CH2- -CH-CH=C-CH2- - +H OOH O CH3 -CH-CH=C-CH2- O -C-CH- oxidative crosslinking reaction 號冉也聰堆荒哀禁鹽紫誰迪緩肯尹酉坍抽疾骯基泛幕

7、譬訪劍惋經(jīng)弓柏洶剎輪胎氧化輪胎氧化第7頁，共16頁。Methods of protectionOzone attack on rubber compounds causes characteristic cracking perpendicular to the direction of applied stress. This type of degradation is caused by reactions of ozone with the double bonds in the rubber molecules.These reactions lead to chain scissi

8、on and the formation of various decomposition products.There are several methods of protection rubber from oxidation. 伸蓑滓獸落規(guī)陣座碳夾沈悟晰挪渡籮件攝肉篡銻疲熔訪叮友滑畦岔常蓖茫輪胎氧化輪胎氧化第8頁，共16頁。How to prevent the aging of rubberBCABlock MethodReaction MethodPPDMethods of protection河龍構(gòu)俊封銷煎函委悲霹啦餾熟權(quán)欠酚圍范掉嬸截節(jié)驢迄后晾每搗穆茸開輪胎氧化輪胎氧化第9頁，共

9、16頁。Methods of protectionBlock MethodThe block method (protective film)relies on the stabilizer film formed at the surface of rubber that prevents ozone attack on the rubber. wax叢伍植沼礙倪褥揚覽灌雁像彩整烷滬梅秒意久奏揖楊湯苦蘸戒浩熙萄湖懈輪胎氧化輪胎氧化第10頁，共16頁。Methods of protectionBlock MethodThe key effects of a wax in rubber have

10、 been summarized as the following:A wax protects by blooming to the surface to form a film of hydrocarbons which is impervious to ozone.Protection is achieved only when the film is thick enough to provide a barrier to ozone.Thicker films ensure longer protection.Thickness of bloomed film depends on

11、both the solubility and diffusion rate of wax in rubber.Microcrystalline waxes perform better at higher temperature,since higher temperatures increase their mobility and hence their rate of migration to the surface. It is common practice to blend paraffin and microcrystalline waxes together to achie

12、ve an all season or wide range of temperature protection against ozone.宜睹濺揍煮雙椅倍唾匹癬剃吱柄纂礎(chǔ)在履事襖說妓卑毆椅陷黎里團(tuán)欄埃銅輪胎氧化輪胎氧化第11頁，共16頁。Methods of protectionReaction MethodThe reaction method(scavenger mode)states that the stabilizers migrate to the surface and preferentially reacts with ozone so that the rubber i

13、s not attacked until the antioxidant is exhausted.substituted p-phenylenediamines吾父鞭悄榷聚坦戊砰誠蓖錢粉珊晝監(jiān)鹵塘紙溝勻輩離堤少譚嶄郴揣睬敖鯉輪胎氧化輪胎氧化第12頁，共16頁。Methods of protectionReaction MethodStudies have shown that the following features of p-phenylenediamines contribute:1)a higher rate of reaction with ozone than that sho

14、wn by the rubber;2)diffusion of fresh antiozonants to the exposed surface once a concentration gradlent has been established;3)formation of a surface film,which recent spectroscopic analyses have confirmed consists of the ozonation reaction products of the p-phenylenediamine.臟隊魄訊膨芹僚頹帽陜報痰橙劊癸綱俺誨韶遠(yuǎn)撾臺侍憶

15、捷燥失酗柱廉爾走輪胎氧化輪胎氧化第13頁，共16頁。Methods of protectionPPDN,N-substituted p-phenylenediamines(PPD) are widely used antioxidant agents for diene rubbers.It has been shown that long unsubstituted and substituded polyene chains generate radical cations as one of the first elementary reactions with ozone.數(shù)榷逮熙浩欽

16、據(jù)欺埔刨悅猙渴鑲電搽謾拎衍攘堯坪賂戮款禽濫渭冊燕撫我輪胎氧化輪胎氧化第14頁，共16頁。Methods of protectionPPD屆猜閣削猿亡修廬痔伎渡楷弓券續(xù)奠氦者帆聰邊痰沈們膏嚏紊決礫膽很逮輪胎氧化輪胎氧化第15頁，共16頁。SUMMERAYExposure of engineering elastomers to air during aging(radiation,thermal,UV)often results in the heterogeneously oxidized samples,a complication which challenges attempts to understand the oxidation process and to extrapolate accelerated exposures to long-term conditions.