Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Thermal oxidation curing polycarbosilane fibers by alternating air and vacuum process
RSC Advances ( IF 3.9 ) Pub Date : 2020-7-10 , DOI: 10.1039/d0ra04888g Xiaohong Li 1 , Zhaofang Xu 1 , Lu Chen 1 , Liu Hong 1 , Yang Li 1
RSC Advances ( IF 3.9 ) Pub Date : 2020-7-10 , DOI: 10.1039/d0ra04888g Xiaohong Li 1 , Zhaofang Xu 1 , Lu Chen 1 , Liu Hong 1 , Yang Li 1
Affiliation
|
Polycarbosilane (PCS) fibers were cured by a process of alternating air and vacuum atmosphere periodically at thermal oxidation temperature. It was found that the oxygen diffusion in the micron PCS fibers could be observed and controlled by this novel curing process. The out surface layer of the cured fibers was rich in oxygen while the inner core had a lower status. Chemical structure analysis indicated that the groups of Si–H, Si–CH2–Si, and Si–CH3 in the out surface layer were oxidized into oxygen containing structures such as Si–OH, Si–O–Si and C![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
O. Ascribe to the controlled oxygen diffusion, the oxidation degree of the inner core was much lower than the surface layer. The oxygen containing structures, Si–H bond reaction degree, molecular weight and ceramic yield of the cured PCS fibers increased with thermal oxidation temperature and alternating cycles. Theoretical calculation results demonstrated that the Si–H bonds reacted with oxygen was the main reason which made the PCS fiber increase weight. This modified process was a high effective surface layer oxidation curing method. Moreover, silicon carbide (SiC) or silicon nitride (Si3N4) ceramic fibers with skin-core or hollow structure also could be prepared from the surface cured PCS fibers with proper following process.
中文翻译：
通过交替空气和真空工艺热氧化固化聚碳硅烷纤维
聚碳硅烷 (PCS) 纤维通过在热氧化温度下周期性地交替空气和真空气氛的过程来固化。发现通过这种新型固化工艺可以观察和控制微米级 PCS 纤维中的氧扩散。固化纤维的外表面层富含氧气，而内核具有较低的状态。化学结构分析表明，外表层的Si-H、Si-CH 2 -Si和Si-CH 3基团被氧化成Si-OH、Si-O-Si和C等含氧结构。O. 由于受控的氧扩散，内核的氧化程度远低于表层。固化后的 PCS 纤维的含氧结构、Si-H 键反应程度、分子量和陶瓷产率随着热氧化温度和交替循环的增加而增加。理论计算结果表明，Si-H键与氧反应是PCS纤维增重的主要原因。这种改进的工艺是一种高效的表面层氧化固化方法。此外，表面固化的PCS纤维也可以通过适当的后续工艺制备出具有皮芯或中空结构的碳化硅（SiC）或氮化硅（Si 3 N 4 ）陶瓷纤维。
更新日期：2020-07-10
O. Ascribe to the controlled oxygen diffusion, the oxidation degree of the inner core was much lower than the surface layer. The oxygen containing structures, Si–H bond reaction degree, molecular weight and ceramic yield of the cured PCS fibers increased with thermal oxidation temperature and alternating cycles. Theoretical calculation results demonstrated that the Si–H bonds reacted with oxygen was the main reason which made the PCS fiber increase weight. This modified process was a high effective surface layer oxidation curing method. Moreover, silicon carbide (SiC) or silicon nitride (Si3N4) ceramic fibers with skin-core or hollow structure also could be prepared from the surface cured PCS fibers with proper following process.
中文翻译：
通过交替空气和真空工艺热氧化固化聚碳硅烷纤维
聚碳硅烷 (PCS) 纤维通过在热氧化温度下周期性地交替空气和真空气氛的过程来固化。发现通过这种新型固化工艺可以观察和控制微米级 PCS 纤维中的氧扩散。固化纤维的外表面层富含氧气，而内核具有较低的状态。化学结构分析表明，外表层的Si-H、Si-CH 2 -Si和Si-CH 3基团被氧化成Si-OH、Si-O-Si和C等含氧结构。
O. 由于受控的氧扩散，内核的氧化程度远低于表层。固化后的 PCS 纤维的含氧结构、Si-H 键反应程度、分子量和陶瓷产率随着热氧化温度和交替循环的增加而增加。理论计算结果表明，Si-H键与氧反应是PCS纤维增重的主要原因。这种改进的工艺是一种高效的表面层氧化固化方法。此外，表面固化的PCS纤维也可以通过适当的后续工艺制备出具有皮芯或中空结构的碳化硅（SiC）或氮化硅（Si 3 N 4 ）陶瓷纤维。
京公网安备 11010802027423号