检索结果-南通市图书馆

Highly Transparent and colorless Polyimide Film with Low Dielectric Constant by Introducing Meta-substituted Structure and Trifluoromethyl Groups

引用

Chinese Journal of Polymer Science 2021年第4期39卷 455-464,I0006页

作者： Hong-Tao Zuo Feng Gan Jie Dong Peng Zhang Xin Zhao Qing-Hua Zhang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

An effective design strategy for preparing highly transparent polyimide film with low dielectric constant is presented.The key to the strategy is to simultaneously introduce meta-substituted structure and trifluoromethyl in polymer chains.By using this design strategy,a highly transparent polyimide film with low-k was synthesized from 3,5-diaminobenzotrifluoride(m-TFPDA)and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)through a two-step method.The obtained m-TFPDA/6FDA(CPI)film(~30 pm)possesses high optical transparency(λ_(cutoff)=334 nm,T_(450nm)=85.26%,Haze=0.31)and is close to colorless(L^(*)=96.03,a^(*)=-0.34,b^(*)=2.12,yellow index=3.96).The intrinsic k and dielectric loss value of the film are 2.27 and 0.0013 at 10 kHz,respectively.More importantly,such low dielectric performance could remain stable up to 280℃,and the film shows a low moisture rate(~0.51%),which helps to maintain the low-k property stability in different humid environments.Meanwhile,the film also shows good thermal stability and mechanical properties,with a glass transition temperature(T_(g))of 296℃and the 5 wt%decomposition temperature(T_(d,s%))of 522℃under N_(2).The tensile strength and tensile modulus of the film are 85.1 MPa and 1.96 GPa,respectively.In addition,the film is soluble in common solvents,which allows simple solution processing and low-cost,continuous roll-to-roll processes.This design strategy is beneficial to improving the transparency,lightening yellow color,lowering the dielectric constant and meanwhile maintaining the comprehensive properties of polyimide films,which is mainly due to the introduced meta-substituted and trifluoromethyl structures effectively inhibiting the transfer of charge transfer complex(CTC)effects and increasing the free volume of film.This design strategy could also be extended to other high-performance polymer systems.

关键词： Polyimide film Transparent colorless Low dielectric constant

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fluorine Substitution Effect on the Material Properties in Transparent Aromatic Polyimides

引用

Chinese Journal of Polymer Science 2022年第7期40卷 781-788页

作者： Wei-Feng Peng Huan-Yu Lei Xin-Xin Zhang Lu-Hao Qiu Ming-Jun Huang South China Advanced Institute for Soft Matter Science and Technology School of Emergent Soft MatterSouth China University of TechnologyGuangzhou510640China Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices South China University of TechnologyGuangzhou510640China

The recent development of flexible display technology raised additional requirements for optical and electric properties of polyimides,accelerating the structure and property tunning of transparent polyimides.The unique electronic effect and steric hindrance effect of fluorine substitutions make fluorine-containing polyimides occupy an important position in the transparent polyimide family.In this work,a series of transparent aromatic polyimides were prepared from a fixed 4,4’-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)and biphenyl diamines with different substitute groups at the 2,2’,6,6’-positions.We systematically studied the effects of pendant groups on the thermal,mechanical,optical and dielectric properties of these 6FDA-based polyimides with the aid of density function theory(DFT)calculation.In particular,we paid special attention to the simple but compact fluoro group substitution.The simple fluoro substitution brought the advantages of maintaining the linearity of the backbone and dense polymer chain packing,which would minimize the weakening of polyimides’inherent thermal,dimensional and mechanical properties.Comparing with trifluoromethyl substituted polyimides with the best optical transparency,polyimides containing fluoro substitutes exhibited slightly decreased optical transparency,but increased thermal and dimensional stability and higher mechanical strength.These results could shed light on the ultimate transparent polyimide film development toward the application in extreme working condition,e.g.,the colorless polyimide substrate film for the flexible display technology.

关键词： Polyimides Fluorine substitution Transparent Dielectric colorless

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New Measuring Method for colorless Liquid Level Based on CLC100 Level Sensor and Powercast Wireless Sensor Kit

引用

Engineering（科研） 2015年第4期7卷 177-189页

作者： Guanlin Yan Gerhard Lindner Yuming Shen Department of Control Science and Engineering University of Shanghai for Science and Technology Shanghai China Institute of Sensor and Actuator Technology Coburg Germany

In this paper, a new wireless measuring method for colorless liquid level measurement was presented, based on latest CLC100 liquid level sensor and Powercast wireless sensor development kit. The wireless system is divided into two parts, level measurement and data transmission part as well as data receiving and display part. First part included the capacitive liquid level sensor CLC100 and the wireless senor board. CLC100 sensor was used for liquid level measurement. Wireless sensor kit from Powercast Corporation included one wireless sensor board, which was used for signal transmission. A built-in PIC microcontroller was embedded in the transmission module, for the purpose of processing and data transmitting. Due to CLC100 sensor’s output voltage exceeding the sensor board’s input limitation, a voltage convertor was designed to connect the sensor and the wireless sensor board. The final results were voltages corresponding to the liquid level, and were processed by an independent PIC development board, and then sent to PC’s hyper terminal via serial-port by this PIC microcontroller. Experiments showed that this wireless sensor node prototype worked well.

关键词： CLC100 Liquid Level Sensor Powercast Wireless Sensor Kit colorless Liquid Level Measurement Wireless Sensor

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Lightpath blocking analysis for optical networks with ROADM intra-node add-drop contention

引用

Science China(Information Sciences) 2016年第10期59卷 76-92页

作者： Yongcheng LI Li GAO Sanjay K.BOSE Weidong SHAO Xiaoling WANG Gangxiang SHEN School of Electronic and Information Engineering Soochow University Department of Electronics and Electrical Engineering Indian Institute of Technology

The contention factor limits the extent to which lightpaths using the same wavelength can be added/dropped in a Reconfigurable Optical Add/Drop Multiplexer(ROADM) when it is operated in a colorless and directionless fashion. This paper presents an analysis to estimate the probability of blocked lightpath requests when a node of this type is used and validates the results for three traffic models. Simulations confirm the validity of the analytical results for lightpath blocking both for various values of the add/drop contention factor C and for changing load distribution in the network. We observe a saturation trend in the lightpath blocking performance as the add/drop port count per bank increases and that a high enough value of C reduces lightpath blocking to levels obtainable from an ideal, comntentionless ROADM. When C is small, limitations on the add/drop port count per bank is observed to be the dominant cause of blocking lightpaths while intra-node contention effects have only a limited impact. With increasing C, blocking is caused more because sufficient link capacity is not available and not because free add/drop ports are not available

关键词： contention factor colorless directionless reconfigurable optical add/drop multiplexers(ROADMs) lightpath blocking

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：