To overcome the design limitations of traditional hydraulic control systemfor synthetic rubber press and such faults as high fault rate, low reliability, highenergy-consuming and which always led to shutting down of p...To overcome the design limitations of traditional hydraulic control systemfor synthetic rubber press and such faults as high fault rate, low reliability, highenergy-consuming and which always led to shutting down of post-treatment product line for syntheticrubber, brand-new hydraulic system combining with PC control and two-way cartridge valves for thepress is developed, whose reliability is analyzed, reliability model of the hydraulic system for thepress is established by analyzing processing steps, and reliability simulation of each step and thewhole system is carried out by software MATLAB, which is verified through reliability test. Thefixed time test has proved not that theory analysis is sound, but the system has characteristics ofreasonable design and high reliability, and can lower the required power supply and operationalenergy cost.展开更多
Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the ...Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the polymerization demonstrated typical features of CCTcoP across the whole polymerization process,i.e.,quasi-living polymerization characteristic,tunable molecular weights,narrow molecular weight distributions,and atom economies.Comparing to previously reported CCTP homopolymerization systems,the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously,rendering slightly higher molecular weights of the resultant PIps and smaller Np(number of polymer chains per Nd atom)values.Moreover,to mimic the structure of natural rubber,the hydroxyl end groups can be facilely modified into phosphonate,amide,and UPy,whose structures were further confirmed by NMR spectra.Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers,as revealed from the significantly reduced static water contact angles.展开更多
Elastomers play an irreplaceable role in our society due to their unique properties.Natural rubber is directly obtained from plants and is widely used in tires,shoes,etc.Recently,modified natural rubbers are proposed ...Elastomers play an irreplaceable role in our society due to their unique properties.Natural rubber is directly obtained from plants and is widely used in tires,shoes,etc.Recently,modified natural rubbers are proposed to expand the application of natural rubber.However,these natural rubbers have a limited variety of molecular structures and may not be able to meet ever-demanding applications.Traditional synthetic elastomers have a variety of molecular structures and their properties are used in various fields,but mainly originate from fossil resources.This review deals with bio-based elastomers,and more specifically natural rubber and bio-based synthetic elastomers.Based on reprocessability,bio-based elastomers can also be divided into bio-based chemically cross-linked ones and thermoplastic ones.Compared to traditional fossil-based elastomers,bio-based ones may alleviate environmental pollution and promote the sustainable development of the elastomer industry.展开更多
基金This project is supported by Provincial Doctoral Foundation of Hebei, China(No.02547020D)Science and Technology Development Foundation of Yanshan University, China(No.YDJJ2004002).
文摘To overcome the design limitations of traditional hydraulic control systemfor synthetic rubber press and such faults as high fault rate, low reliability, highenergy-consuming and which always led to shutting down of post-treatment product line for syntheticrubber, brand-new hydraulic system combining with PC control and two-way cartridge valves for thepress is developed, whose reliability is analyzed, reliability model of the hydraulic system for thepress is established by analyzing processing steps, and reliability simulation of each step and thewhole system is carried out by software MATLAB, which is verified through reliability test. Thefixed time test has proved not that theory analysis is sound, but the system has characteristics ofreasonable design and high reliability, and can lower the required power supply and operationalenergy cost.
基金financially supported by the National Natural Science Foundation of China(No.U1862206)Jilin Province Department of Education(No.JJKH20200665KJ)+3 种基金Dr.W.Zhao thanks for the financial support from China Postdoctoral Science Foundation(No.2021M701818)Shandong Provincial Natural Science Foundation,China(No.ZR2022QE237)Qingdao Postdoctoral Applied Research Project,PetroChina Company Limited(No.2020B-2711)H.Liu sincerely acknowledges the financial support from the Taishan Scholars Program。
文摘Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the polymerization demonstrated typical features of CCTcoP across the whole polymerization process,i.e.,quasi-living polymerization characteristic,tunable molecular weights,narrow molecular weight distributions,and atom economies.Comparing to previously reported CCTP homopolymerization systems,the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously,rendering slightly higher molecular weights of the resultant PIps and smaller Np(number of polymer chains per Nd atom)values.Moreover,to mimic the structure of natural rubber,the hydroxyl end groups can be facilely modified into phosphonate,amide,and UPy,whose structures were further confirmed by NMR spectra.Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers,as revealed from the significantly reduced static water contact angles.
基金National Natural Science Foundation of China,Basic Science Center Program,Grant/Award Number:51988102National Natural Science Foundation of China,Grant/Award Number:52073011Innovative Research Groups,Grant/Award Numbers:51221002,51521062。
文摘Elastomers play an irreplaceable role in our society due to their unique properties.Natural rubber is directly obtained from plants and is widely used in tires,shoes,etc.Recently,modified natural rubbers are proposed to expand the application of natural rubber.However,these natural rubbers have a limited variety of molecular structures and may not be able to meet ever-demanding applications.Traditional synthetic elastomers have a variety of molecular structures and their properties are used in various fields,but mainly originate from fossil resources.This review deals with bio-based elastomers,and more specifically natural rubber and bio-based synthetic elastomers.Based on reprocessability,bio-based elastomers can also be divided into bio-based chemically cross-linked ones and thermoplastic ones.Compared to traditional fossil-based elastomers,bio-based ones may alleviate environmental pollution and promote the sustainable development of the elastomer industry.
