Silicone rubber 250 degree-a a lan chhuahna chu a lan chhuahna "normal" a ni lo va, dinhmun bik hnuaia a aging mechanism avanga lo awm a ni zawk.
A tlangpuiin silicone rubber hi a lumna a do nasa hle a, hun rei tak-Term service temperature hi -60℃atanga 200-230℃thleng a ni tlangpui. Temperature chu a chung lam limit 250℃emaw a aia sang emaw a nih chuan aging process lian tham engemaw zat a chak ang a, a tawpah chuan embrittlement a thlen ang. Embrittlement awm chhan bulpui ber chu silicone rubber polymer-a main chain leh side group-te chemical degradation tihdanglam theih lohah a awm a ni. A hnuaia tarlan te hi embrittlement thlentu core mechanism engemaw zat an ni.
1. Side group oxidation (mechanism ber) kalpui dan: Silicone rubber chi khat chu methyl vinyl silicone rubber a ni. Temperature sang takah chuan boruaka oxygen chuan polymer-te side chain-a methyl group (-ch) te chu a bei ang. Chemical reaction: Methyl group chu oxidized a ni a, a hmasa berah hydroxyl group (-OH) a siam a, chu chuan a cross-link emaw oxide dang a siam thei emaw a ni. Hetiang hian molecular chain inkarah crosslinking point dang (oxidative crosslinking) a siam belh bawk.
A rah chhuah: Additional crosslinking points a pun zel avangin polymer network chu a dense lutuk a, a tight lutuk bawk. Material hian a elasticity a hloh a, a nghet a, a tawpah chuan brittle fracture a tawk a, chu chu stress tenau tak a nih chuan a ni. Fishing net i ngaihtuah thei ang. A node tam lutuk leh a dense lutuk chuan a flexibility a hloh a, a chhuah chuan awlsam takin a chhe thin.
2.Main chain depolymerization (" unwinding "reaction) process: temperature sang tawk takah chuan siloxane main chain (-Si-o{-) ngei pawh a chhe thei. Chemical reaction: Chain bulpui ber chu a chhe a, cyclic oligomers (D3, D4, etc. ang chi) leh molecule tenau dangte a siam chhuak thin.
A rah chhuah: Polymer chain sei zawng a tawi a, molecular weight a tlahniam bawk. Hei hian direct takin material mechanical strength a tihhniam phah a ni. Chain a tawi lutuk chuan, material chuan stress chu effective takin a tuar thei lo va, a brittle bawk ang. Hetiang thil hi oxygen awm leh awm lohah pawh a thleng thei a, mahse a bik takin temperature sang lutukah chuan a langsar hle.
3. Thil danglam thei lo leh plasticizers hloh dan: silicone rubber siam chhuah lai hian low{{1}molecular-weight siloxanes a awm thei a, a nih loh leh processability tihchangtlun nan additive thenkhat dah belh theih a ni bawk. Long-Term high temperature hnuaiah chuan heng low-molecular-weight substance te hi zawi zawiin an volatilize emaw an migrate out emaw ang.
A rah chhuah: A tlem berah chuan heng thilte hian internal lubrication leh plasticizing-ah hian chanvo an nei a ni. An hloh chuan material chu a harh ang a, a shrink ang a, a brittle bawk ang.
4.Thermal cycling leh stress hahna .
Process: Application scenario-a khawsik leh lum cycle a awm fo chuan silicone rubber chu a zau zel ang a, a inzawm reng bawk ang.
A rah chhuah: He periodic stress hian material chhungah microcracks a thlen thei. Temperature sang tak catalysis hnuaiah chuan heng microcracks te hian an expansion leh connection a ti chak ang a, a tawpah chuan macroscopic brittle cracking of the material a thlen ang.