Fabrication of UV-Curing Linalool-Polysiloxane Hybrid Films with High Refractive Index and Transparency

In this article,a series of high refractive indices(1.50-1.53)thiol phenyl polysiloxane(TPS)were synthesized via hydrolytic sol-gel reaction.The Fourier transform infrared spectra(FT-IR)and nuclear magnetic resonance spectra(NMR)results showed that TPS conformed to the predicted structures.Natural terpene linalool was exploited as photocrosslinker to fabricate UV-curing linalool-polysiloxane hybrid films(LPH)with TPS via photoinitiated thiol-ene reaction.LPH rapidly cured under UV irradiation at the intensity of 80 mW/cm^(2) in 30 s,exhibiting good UV-curing properties.The optical transmittance of LPH in the wavelength of 300-800 nm was over 90%,exhibiting good optical transparency.The water contact angle and water vapor permeability results showed that the introduction of phenyl groups enhance the hydrophobicity and water vapor barrier properties of LPH.The results indicated the potential of LPHs in the applications of optical functional coatings.

Early changes in corneal densitometry after FS-LASIK combined with accelerated corneal cross-linking for correction of high myopia

AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.

A UV cross-linked gel polymer electrolyte enabling high-rate and high voltage window for quasi-solid-state supercapacitors

Serving as a promising alternative to liquid electrolyte in the application of portable and wearable devices,gel polymer electrolytes(GPEs)are expected to obtain more preferable properties rather than just be satisfied with the merits of high safety and deformability.Here,an easy-operated method is employed to fabricate cross-linked composite polymer membranes used for GPEs assisted by UV irradiation,in which N-doped carbon quantum dots(N-CQDs)and TiO2are introduced as photocatalysts and additives to improve the performances of GPEs.Specifically,N-CQDs participate as a cross-linker to construct the inner porous structure,and TiO2nanoparticles serve as a stabilizer to improve the electrochemical stability of GPEs under high voltage(3.5 V).The excellent thermal and mechanical stability of the membrane fabricated in this work guarantee the safety of the supercapacitors(SCs).This GPE based SC not only exhibits prominent rate performance(105%capacitance retention at the current density of 40A g^(-1))and cyclic stability(85%at 1 A g^(-1)under 3.5 V after 20,000 cycles),but also displays remarkable energy density(42.88 Wh kg^(-1))with high power density(19.3 k W kg^(-1)).Moreover,the superior rate and cycling performances of the as-prepared GPE based flexible SCs under flat and bending state confirm the feasibility of its application in flexible energy storage devices.

Highly cross-linked versus conventional polyethylene inserts in total hip arthroplasty,a five-year Roentgen stereophotogrammetric analysis randomised controlled trial

BACKGROUND Polyethylene(PE)particles produced by wear of the acetabular insert are thought to cause osteolysis and thereby aseptic loosening of the implant in total hip arthroplasty(THA).As highly cross-linked polyethylene(HXLPE)is presumed to give lower wear rates,in vivo studies are needed to confirm this.AIM To compare the wear of REXPOL,a HXPLE,with conventional PE within the first five years after implantation using Roentgen stereophotogrammetric analysis(RSA).METHODS Patients were randomised to receive either a HXLPE(REXPOL)or a conventional PE insert during primary THA.RSA images were obtained directly postoperative and after 6 wk,12 wk,6 mo,12 mo,24 mo and five years.Functional outcomes were assessed using the Hip Injury and Osteoarthritis Outcome Score and Harris Hip Score at baseline and five years after surgery.RESULTS The HXLPE(REXPOL)showed less wear in the latero-medial direction.Significant wear rates of conventional PE were seen in the latero-medial and center-proximal direction and in volume and corrected volume,whereas the REXPOL did not show these outcomes over time.Improvement from baseline in functional outcome did not significantly differ.CONCLUSION Total 3D wear is less in THAs inserted with a REXPOL inlay than a conventional PE inlay after five years.This study confirms,for the first,that the REXPOL HXLPE inlay is preferred to standard PE.

Cross-Linked Hollow Graphitic Carbon as Low-Cost and High-Performance Anode for Potassium Ion Batteries

Large-scale and low-cost preparation of carbon-based potassium anode with long life and high capacity is one of the footstones for the development of potassium ion batteries(PIBs).Herein,a low-cost carbon-based material,cross-linked hollow graphitic carbon(HGC),is large scale synthesized to apply for PIBs anode.Its hollow structure can afford sufficient space to overcome the damage caused by the volume expansion of graphitic carbon(GC).While the cross-linked structure forms a compact interconnection network that allows electrons to rapid transfer between different GC frameworks.Electrochemical measurements demonstrated that the HGC anode exhibited low charge/discharge plateau(about 0.25 V and 0.1 V)and excellent specific capacity as high as 298 m A h g^(-1)at the current density of 50 m A g^(-1).And more important,after 200 cycles the capacity of HGC anode still shows 269 m A h g^(-1)(the decay rate of per cycle is only 0.048%).Meanwhile,the use of commercial traditional electrolyte(KPF_(6))and cheap raw materials that provide new hope for trying and realizing the large-scale production of PIBs based on carbon anode materials.

Insights into the swelling process and drug release mechanisms from cross-linked pectin/high amylose starch matrices

Cross-linked pectin/high amylose mixtures were evaluated as a new excipient for matrix tablets formulations,since the mixing of polymers and cross-linking reaction represent rational tools to reach materials with modulated and specific properties that meet specific therapeutic needs.Objective:In this work the influence of polymer ratio and cross-linking process on the swelling and the mechanism driving the drug release from swellable matrix tablets prepared with this excipient was investigated.Methods:Cross-linked samples were characterized by their micromeritic properties(size and shape,density,angle of repose and flow rate)and liquid uptake ability.Matrix tablets were evaluated according their physical properties and the drug release rates and mechanisms were also investigated.Results:Cross-linked samples demonstrated size homogeneity and irregular shape,with liquid uptake ability insensible to pH.Cross-linking process of samples allowed the control of drug release rates and the drug release mechanism was influenced by both polymer ratio and cross-linking process.The drug release of samples with minor proportion of pectin was driven by an anomalous transport and the increase of the pectin proportion contributed to the erosion of the matrix.Conclusion:The cross-linked mixtures of high amylose and pectin showed a suitable excipient for slowing the drug release rates.

Oxidation, Chain Scission and Cross-Linking Studies of Polysiloxanes upon Ageings

The comparison between physical properties and chemical structures of several polysiloxanes was studied at initial state and upon ageings. Techniques such as densimetry, gel permeation chromatography, FTIR spectroscopy, thermogravim- etric analysis coupled with IR spectroscopy and the new tool photo-DSC were used to give assessments of average mo- lecular weight, chemical evolution, cristallinity and thermal stability. Different types of ageing such as thermal ageing (60?C and 100?C), photo-ageing and acid vapour ageing were performed. After ageing we observed an evolution of chemical structures and physical properties for all samples. The main pathway of degradation is given for each sample. It results in oxidation, chain scission or cross-linking. Cross-linking levels are dependant on the type of ageing, the chemical structure and the initial rate of cristallinity. Cross-linking reactions are favoured after photo-ageing. Oxidation is higher for polysiloxane with aliphatic carbon chain.

Highly integrated sulfur cathodes with strong sulfur/high-strength binder interactions enabling durable high-loading lithium-sulfur batteries

The development of high-sulfur-loading Li-S batteries is a key prerequisite for their commercial applications.This requires to surmount the huge polarization,severe polysulfide shuttling and drastic volume change caused by electrode thickening.High-strength polar binders are ideal for constructing robust and long-life high-loading sulfur cathodes but show very weak interfacial interaction with non-polar sulfur materials.To address this issue,this work devises a highly integrated sulfur@polydopamine/highstrength binder composite cathodes,targeting long-lasting and high-sulfur-loading Li-S batteries.The super-adhesion polydopamine(PD)can form a uniform nano-coating over the graphene/sulfur(G-S)surface and provide strong affinity to the cross-linked polyacrylamide(c-PAM)binder,thus tightly integrating sulfur with the binder network and greatly boosting the overall mechanical strength/conductivity of the electrode.Moreover,the PD coating and c-PAM binder rich in polar groups can form two effective blockades against the effusion of soluble polysulfides.As such,the 4.5 mg cm−2 sulfur-loaded G-S@PD-c-PAM cathode achieves a capacity of 480 mAh g−1 after 300 cycles at 1 C,while maintaining a capacity of 396 mAh g−1 after 50 cycles at 0.2 C when the sulfur loading rises to 9.1 mg cm−2.This work provides a system-wide concept for constructing high-loading sulfur cathodes through integrated structural design.

二苯基硅基改性的加成型聚二甲基硅氧烷离型涂层的合成及性能

以甲醇钾为催化剂,四(二甲基乙烯基硅氧基)硅烷(TVDMS)为封端剂,三(三甲基硅基)磷酸酯为中止剂,使用二甲基硅氧烷混合环体(DMC)、四乙烯基四甲基环四硅氧烷(V4)、八苯基环四硅氧烷(P8)为原料,通过高温阴离子开环聚合反应环境友好地成功合成了二苯基硅基改性的含乙烯基的聚二甲基硅氧烷,并利用FT-IR、HNMR和GPC对其结构和分子量数据进行了表征,将其制备成离型涂层后,通过180°剥离力测试、疏水角测量、折光率测量等对其性能进行了表征。结果表明,固化样品硬度高,透明性好,折光率随苯基含量的提高而提高,涂层具有100~110°的水接触角,随着苯基含量的提高,剥离力和残余接着率都有所下降。

Scheimpflug imaged corneal changes on anterior and posterior surfaces after collagen cross-linking

AIM:To compare the anterior and posterior corneal parameters before and after collagen cross-linking therapy for keratoconus.METHODS:Collagen cross-linking was performed in31 eyes of 31 keratoconus patients(mean age 30.6±8.9y).Prior to treatment and an average 7mo after therapy,Scheimpflug analysis was performed using Pentacam HR.In addition to corneal thickness assessments,corneal radius,elevation,and aberrometric measurements were performed both on anterior and posterior corneal surfaces.Data obtained before and after surgery were statistically analyzed.RESULTS:In terms of horizontal and vertical corneal radius,and central corneal thickness no deviations were observed an average 7mo after operation.Corneal higher order aberration showed no difference neither on anterior nor on posterior corneal surfaces.During follow-up period,no significant deviation was detected regarding elevation values obtained by measurement in mm units between the 3.0-8.0 mm-zones.CONCLUSION:Corneal stabilization could be observed in terms of anterior and posterior corneal surfaces,elevation and higher order aberration values 7mo after collagen cross-linking therapy for keratoconus.

聚酯磷酸酯改性聚硅氧烷的性能及机理研究

为改善弹性聚硅氧烷的黏结性能并探究聚酯磷酸酯附着力促进剂对弹性聚硅氧烷性能的影响。采用聚酯磷酸酯改性弹性聚硅氧烷,分别用万能试验机、热重差热综合分析仪测试了弹性聚硅氧烷改性前后的剪切强度、耐热性等性能,用傅立叶变换红外光谱仪对聚酯磷酸酯及弹性聚硅氧烷进行了表征。结果表明:聚酯磷酸酯可以有效改善弹性聚硅氧烷的黏结性能,最佳添加量为3份。根据试验结果推测聚酯磷酸酯不仅可以通过机械铆合的方式改善弹性聚硅氧烷的黏结性,还可能通过与固化剂中Si—OH基团反应将弹性聚硅氧烷与金属表面连接起来以提升黏结性。

端羟基含氟乙烯基聚硅氧烷的合成及应用

室温硫化氟硅橡胶应用甚广,当分子量大时端羟基活性往往难以满足要求。以八甲基环四硅氧烷(D4)、三氟丙基三甲基环三硅氧烷(D3F)为聚合单体,四甲基四乙烯基环四硅氧烷(D4Vi)为活性基团引入单体,去离子水为封端剂,四甲基氢氧化铵((Me)4NOH)为催化剂催化进行阴离子开环共聚,制备高粘度端羟基含氟乙烯基聚硅氧烷。探究了封端剂用量、催化剂用量、硅氧烷链节比等因素对聚合反应的影响。通过核磁、红外测试分析共聚物的分子结构;通过热分析法测试共聚物热分解温度;通过凝胶色谱测试产物的分子量分布。研究结果表明:固定链节比,催化剂用量为总单体用量的0.012%、封端剂用量为0.285%时所得聚合物产率较高。对聚合物进行涂膜测试,结果表明,其涂膜室温固化性好,且具有良好的疏水性。

一种耐温型润湿性调节剂的制备及性能评价

八甲基环四硅氧烷和四甲基环四硅氧烷在强酸性离子交换树脂的引发下发生聚合,得到中间体含氢聚硅氧烷。中间体再与3-丁烯-1-醇在催化剂铂(0)-1,3-二乙烯-1,1,3,3-四甲基二硅氧烷的催化下发生反应,得到了一种羟基接枝聚硅氧烷,对其进行了结构表征,并对其耐温能力以及对储层岩石(砂岩)表面润湿性的调节能力进行了性能评价。结果表明,该羟基接枝聚硅氧烷有着很好的耐高温性能,并且可以在240℃的高温环境下将砂岩表面润湿性调节至中间润湿状态,能够有效阻止钻井液中水相对储层岩石的侵入,降低水锁损害,保护油气储层。

聚硅氧烷涂敷的反相高效液相色谱固定相

用甲基乙烯基聚硅氧烷涂敷于硅烷化的微粒硅胶上．制备出一种新型的涂敷散型反相高效液相色谱固定相。该固定相对极性、非极性和碱性化合物均有良好的分离能力，峰对称性好。对其稳定性进行了考察．连续使用三个月后，固定相的含碳量和色谱性能仍保持不变。

可紫外光/湿气双重固化聚硅氧烷丙烯酸酯树脂的合成与表征

分别以γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)、端羟基聚二甲基硅氧烷(107)为原料,采用脱醇缩合的方法合成了含不饱和C=C双键和Si-OCH3的聚硅氧烷丙烯酸酯(PSA)。用FTIR,NMR表征其结构,并对双重固化行为进行了研究。结果表明:预聚物在3%光引发剂下进行紫外光固化,其双键的最终转化率可达100%;据Arrhenius方程可以得到在28%相对湿度的环境下,预聚物湿气固化反应表观活化能为23.2kJ/mol。

苯基乙烯基甲基聚硅氧烷涂敷的反相高效液相色谱固定相

用苯基乙烯基甲基聚硅氧烷涂敷于硅烷化的微粒硅胶上，制备出反相高效液相色谱固定相。制备出的固定相对极性、非极性化合物有良好的分离能力，峰对称性好。对其稳定性进行了考察，连续使用１２００ｈ后，固定相的含碳量及色谱性能保持不变，且用ｐＨ１１．０的流动相冲洗２６０ｈ，固定相的色谱性能仍很好，可见固定相的耐碱性能良好。

长链聚硅氧烷接枝(甲基)丙烯酸酯聚合物乳液的制备及性能

该文首先合成了聚硅氧烷阴离子乳液和链中含硅烷偶联剂的(甲基)丙烯酸酯聚合物乳液,然后通过乳液接枝共聚的方法,利用羟基缩合反应合成了一种高硅含量的硅丙聚合物乳液。结果表明,有机硅质量分数为20%的聚合物乳液涂膜性能最佳,与不含有机硅的聚合物乳液涂膜相比,其水表面接触角由77.5°增加到95°,24 h吸水率由4.9%下降到2.3%,耐水性大大增加,同时玻璃化转变温度由8.53℃下降到-1.36℃,聚合物分子链的柔顺性有所提高,说明该法合成的高硅含量硅丙乳液涂膜可作为一类具有优良耐水性及良好的表面疏水性的功能材料得以应用。

新型高温固定相C_(60)聚硅氧烷的合成及色谱特性

合成了两种新的 C60 侧链线性聚硅氧烷 ,并用作毛细管气相色谱固定相 .该类固定相柱效高 ,使用温度范围宽 ,热稳定性好 ,最高柱温达 36 0℃ ,基线漂移量为 3× 1 0 - 14 ～ 4× 1 0 - 14 nm,对各类位置异构体有独特的分离效果 ,尤其对高沸点化合物如糖、多环芳烃和邻苯二甲酸酯类有良好的分离选择性 .

PHMS为反应性助稳定剂制备高固含量苯丙共聚细乳液

以含氢聚硅氧烷（PHMS）为反应性助稳定剂,采用一步法和半连续法细乳液聚合制备了固含量为50%苯丙共聚乳液。考察了不同细乳液聚合体系中反应稳定性、单体转化率、共聚乳胶粒子粒径及粒径分布变化、粒子数目变化及乳液稳定性的不同。结果表明,与一步法细乳液聚合相比,半连续细乳液聚合过程中单体转化率增长缓慢,聚合稳定性好;乳胶粒径由156.8 nm增大到215.3 nm;粒径分布指数在0.151~0.254之间,乳胶粒子数目相对稳定;制备高固含量苯丙乳液贮存稳定性、冻融及钙离子稳定性比一步法细乳液聚合体系好。

有机硅高温涂料的剖析

本文介绍了一种有机硅高温涂料的剖析方法。首先采用蒸馏和溶剂提取的方法将该涂料分离为有机溶剂、树脂及无机物三部分。通过对各部分的红外吸收光谱和发射光谱的试验,确定该涂料由何种物质组成。针对各个物质利用不同的定量分析方法,最终得出各物质的含量。