Self-Healing,Self-Adhesive and Stable Organohydrogel-Based Stretchable Oxygen Sensor with High Performance at Room Temperature

With the advent of the 5G era and the rise of the Internet of Things,various sensors have received unprecedented attention,especially wearable and stretchable sensors in the healthcare field.Here,a stretchable,self-healable,self-adhesive,and room-temperature oxygen sensor with excellent repeatability,a full concentration detection range(0-100%),low theoretical limit of detection(5.7 ppm),high sensitivity(0.2%/ppm),good linearity,excellent temperature,and humidity tolerances is fabricated by using polyacrylamide-chitosan(PAM-CS)double network(DN)organohydrogel as a novel transducing material.The PAM-CS DN organohydrogel is transformed from the PAM-CS composite hydrogel using a facile soaking and solvent replacement strategy.Compared with the pristine hydrogel,the DN organohydrogel displays greatly enhanced mechanical strength,moisture retention,freezing resistance,and sensitivity to oxygen.Notably,applying the tensile strain improves both the sensitivity and response speed of the organohydrogel-based oxygen sensor.Furthermore,the response to the same concentration of oxygen before and after self-healing is basically the same.Importantly,we propose an electrochemical reaction mechanism to explain the positive current shift of the oxygen sensor and corroborate this sensing mechanism through rationally designed experiments.The organohydrogel oxygen sensor is used to monitor human respiration in real-time,verifying the feasibility of its practical application.This work provides ideas for fabricating more stretchable,self-healable,self-adhesive,and high-performance gas sensors using ion-conducting organohydrogels.

Effect of Self-adhesive Resin Cement and Tribochemical Treatment on Bond Strength to Zirconia

Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated： Maxcem （MA）, Smartcem （SM）, Rely X Unicem Aplicap （UN）, Breeze （BR）, Biscem （BI）, Set （SE）, and Clearfil SA luting （CL）. The specimens were grouped according to conditioning as follows： Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 μm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating ＋ silanization. Specimens were stored in distilled water at 37℃ for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, B1, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP- containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

One-pot preparation and applications of self-healing,self-adhesive PAA-PDMS elastomers

A new family of transparent,biocompatible,self-adhesive,and self-healing elastomer has been developed by a convenient and efficient one-pot reaction between poly(acrylic acid)(PAA)and hydroxyl-terminated polydimethylsiloxane(PDMSOH).The condensation reaction between PAA and PDMS-OH has been confirmed by attenuated total reflection Fourier transform infrared(ATR-FTIR)spectra.The prepared PAA-PDMS elastomers possess robust mechanical strength and strong adhesiveness to human skin,and they have fast self-healing ability at room temperature(in^10 s with the efficiency of 98%).Specifically,strain sensors were fabricated by assembling PAA-PDMS as packaging layers and polyetherimide-reduced graphene oxide(PEI-rGO)as strain-sensing layers.The PAA-PDMS/PEI-rGO sensors are stably and reliably responsive to slight physical deformations,and they can be attached onto skin directly to monitor the body’s motions.Meanwhile,strain sensors can self-heal quickly and completely,and they can be reused for the motion detecting after shallowly scratching the surface.This work provides new opportunities to manufacture high performance self-adhesive and self-healing materials.

Effect of Different Pretreatments to Post-space on Bonding Strength of Fiber Posts Luted with a Self-adhesive Resin Cement

The effects of different post-space pretreatments on the retentive force of fiber posts cemented with a self-adhesive resin cement were investigated. Twenty-eight single-canal premolars were obturated by Resilon using warm vertical compaction and treated with distilled water, 2.5% NaOCl, 17% EDTA and 2.5% NaOCI; or 17% EDTA, 2.5% NaOCI, and ultrasonic agitation （U/E/N treatment）. Subsequently, radicular dentin surfaces were observed under scanning electron microscopy （SEM）. RelyX Fiber Posts were cemented in the treated canals by using RelyX U100, and thin-slice push-out test and SEM observation of coronal and apical regions of the specimens were performed. Data were analyzed using two-way ANOVA and Tukey＇s HSD post- hoc tests, and the percentage of failure type was calculated. Ultrasonic/EDTA/NaOC1 irrigation showed the maximum effectiveness in removing the smear layer and debris on the dentin surface. The apical bond strength of the experimental groups was significantly higher than that of the control group （P〈 0.05）. Adhesive failure between cement and dentin was the most common mode of failure. No obvious RDIZ or resin tag was detected. Chemical irrigants facilitated the bonding of these fiber posts, and ultrasonic activation improved retention. Future studies should evaluate the effectiveness of irrigation on fiber post push-out strength in fatigue cycling condition.

Effects of galvanic interaction between galena and pyrite on their flotation in the presence of butyl xanthate

The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical,adsorption,flotation and FTIR techniques,respectively.Electrochemical tests indicate that galena is electrochemically more active than pyrite and serves as an anode in galvanic combination with pyrite.The galvanic current density from a mixture of galena and pyrite is 4 times as high as the self corrosion current density of galena,which indicates that the corrosion rate of galena is accelerated.Adsorption tests show that the adsorption of butyl xanthate on galena surface is enhanced,and affected by a combination of pyrite-galena mixtures and conditioning time.Compared with individual mineral particles,galvanic interaction reduces the floatability difference between galena and pyrite.The flotation recovery of galena decreases while that of pyrite increases when two minerals are mixed together due to the influence of galvanic interaction on the formation of hydrophilic/hydrophobic product.The FTIR results show that the formation of dixanthogen on pyrite surface is depressed due to the galvanic interaction.

稳杀得(Fluazifop-butyl)环境行为研究

采用田间试验和模拟试验的方法,研究了稳杀得及稳杀得酸的降解动态规律;鉴定了部分降解产物,推测了部分降解途径;借助红外光谱及电子自旋共振谱研究了稳杀得及稳杀得酸与土壤金属离子Cu^(2+)、Fe^(3+)及Al^(3+)的相互作用。为探明稳杀得在我国的安全使用提供了科学依据。

有机半导体Butyl-PBD的DFT理论计算研究

采用密度泛函理论(DFT)方法对2-(4-叔丁苯基)-5-(4-联苯基)-1,3,4-恶二唑(Butyl-PBD)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现Butyl-PBD在0.1～10 THz波谱范围内有五个明显的吸收峰,分别位于2.04 THz、3.48 THz、5.16 THz、6.60 THz及7.08 THz,Butyl-PBD在紫外光波段有三个吸收波段,分别对应于326.76 nm、279.60 nm及269.31 nm,其中326.76nm的紫外吸收峰最强。电子密度计算表明,最大电子密度集中在O原子上,N原子的电子密度次之。Mulliken电荷计算表明,负电荷主要集中在O原子和N原子上,所有H原子的Mulliken电荷都为正电荷,C原子的Mulliken电荷则与其具体位置相关。

Investigation on the Factors Influencing the Synthesis of Butyl Polyglycosides and Its Synthesis Kinetics

[ Objective ] The paper was to study the factors influencing the synthesis of butyl polyglycosides and its synthesis kineties. [ Method ] In the synthesis process of alkyl polyglycosides by transglyeosidation method, p-toluenesulfonie acid and stearie acid were used as composite catalyst, intermediate product butyl polyglycosides was prepared via reactive distillation technology. [ Result ] The suitable preparation conditian of butyl polyglyeasides was as follows： catalyst usage, 1.2 g（ p-toluenesulfoni ：stearie acid = 6：1 ） ; reaction temperature, 110 ℃ ; the ratio of butanol and glucose, 8： 1. The results showed that the larger the molar ratio of butanol and glucose was,the more the butyl monoside content was, and the less the polymerizatian degree of butyl glyeasides was. The catalyst usage and reaction temperature had little influence on the component of butyl polyglyeesides. With the increase of catalyst usage or reaction temperature,the reaction time was shortened dramatically. The kinetic equation for the synthesis of butyl glueeside was finally obtained as follows： -dCA/dt =0.163 7exp（ -1. 968×10^3/RT）CA -0.003 49 exp （ -2.727×10^3/RT） Ce. [ Conclusionl The suitable condition for the preparation of butyl polyglyeasides and its synthesis kinetic equation obtained in the study could provide theoretical basis for the synthesis of long-chain alkyl polyglyeasides.

Floc flotation of marmatite fines in aqueous suspensions induced by butyl xanthate and ammonium dibutyl dithiophosphate

The hydrophobic flocculation of marmatite fines in aqueous suspensions induced by butyl xanthate （KBX） and ammonium dibutyl dithiophosphate （ADD） was investigated using laser particle size analysis, microscopy analysis, electrophoretic light scattering, contact angle measurement and infrared spectroscopy. The studies were performed on single minerals with size 〈20 μm by varying several parameters, including pH, collector concentration and kerosene addition. The results show that the floc fotation closely correlated with the size of flocs and the particle hydrophobicity, but was not lowered with increasing the particle surface charges due to collector adsorption. Under good operating conditions, the floc flotation of marmatite fines as a function of KBX and ADD can all reach floatability over 90%, in comparison with conventional flotation obtaining floatability of about 60%. It also has been found that a small addition of kerosene greatly improved the floc flotation because of the formation of oil films on marmatite particles. The results of FTIR spectra indicate that adsorption of the two collectors onto marmatite were chemical adsorption.

丁基三氯化锡催化合成抗氧剂618的工艺

为进一步改善抗氧剂618的合成工艺条件,从有机锡催化剂当中选择出综合性能较好的催化剂,并对其催化合成抗氧剂618的工艺条件进行优化,而后进一步探究化合物的结构对其催化性能的影响。结果表明:丁基三氯化锡的综合性能最好,其优化后所得最佳工艺条件为n(季戊四醇)∶n(亚磷酸三乙酯)∶n(十八醇)的投料摩尔比为1∶2.15∶2;催化剂的添加量是季戊四醇质量的4%,第1步的反应温度为120℃,第2步反应温度为160℃;反应总时间为5h。丁基三氯化锡作为反应的催化剂,氯原子的吸电子效应使得中心锡原子所处位置的电子云密度较低,其Lewis酸性较强,催化活性较高。且氯化锡类化合物当中取代基团的吸电子效应越强,其化合物的Lewis酸性越强,相应的催化性能越好;同时取代基的空间位阻越小,其催化性能越好。

桂花提取物的抗氧化活性及对t-BHP诱导HepG2细胞氧化损伤的保护作用

采用DPPH法、ABTS法、FRAP法评价了桂花水提取物、95%乙醇提取物、正丁醇提取物、乙酸乙酯提取物、石油醚提取物的抗氧化活性,并探究了桂花水提取物对叔丁基过氧化氢(t-BHP)诱导的人肝癌细胞HepG2氧化损伤的保护作用。结果表明,桂花提取物具有一定的抗氧化活性,但不同溶剂提取物的抗氧化活性存在差异;桂花水提取物与HepG2细胞具有良好的生物相容性,可以抑制t-BHP诱导的HepG2细胞中8-羟基-2′-脱氧鸟苷(8-OHdG)、肿瘤坏死因子-α(TNF-α)和白介素-1β(IL-1β)的产生,还显著降低了丙二醛(MDA)水平。

共混比对NR/CIIR共混物的拉伸取向及SIC行为的研究

采用机械共混和模压成型工艺制备了天然橡胶(NR)/氯化丁基橡胶(CIIR)复合材料,并对其硫化性能、机械性能、单轴拉伸取向性能、应变诱导结晶(SIC)、阻尼行为等进行了分析。透射电子显微镜(TEM)的结果显示,CIIR组分在共混物中呈现海岛结构分布,且边界清晰。随着CIIR占比增大,拉伸应力应变性能与纯NR相一致,但拉伸强度比纯NR下降明显;通过红外二向色性法分析发现,共混物的取向行为主要源于NR组分;同步辐射广角X射线衍射(WAXD)的测试结果表明,共混物中CIIR占比越高,SIC行为越弱;通过机械共混的方式,可以制备得到两者特性结合的NR/CIIR共混物,30 Hz条件下损耗因子从NR纯胶的0.1,增加至NR/CIIR 50/50(质量比)的0.18,上升幅度达80%,为隔震支座用橡胶材料的制备提供新思路。

Developmental Toxicity in Mice Following Paternal Exposure to Di-N-Butyl-Phthalate (DBP)

Objective The aim of the present study was to investigate the effects of paternal Di‐N‐butyl‐phthalate （DBP） exposure pre‐ and postnatally on F1 generation offspring,and prenatally on F2 generation offspring.Methods Male mice were exposed to either 500 mg/kg or 2 000 mg/kg of DBP for 8 weeks,and mated with non‐exposed females.Three‐quarters of the females were sacrificed a day prior to parturition,and examined for the number of living and dead implantations,and incidence of gross malformations.Pups from the remaining females were assessed for developmental markers,growth parameters,as well as sperm quantity and quality.Results There were no changes in the fertility of parents and in intrauterine development of the offspring.Pups of DBP‐exposed males demonstrated growth‐retardation.Following paternal exposure to 500 mg/kg bw of DBP,there were almost twice the number of males than females born in the F1 generation.F1 generation females had a 2.5‐day delay in vaginal opening.Paternal exposure to 2 000 mg/kg bw of DBP increased the incidence of sperm head malformations in F1 generation males;however,there were no changes in the fertility and viability of foetuses in the F2 generation.Conclusion Paternal DBP exposure may disturb the sex ratio of the offspring,delay female sexual maturation,and deteriorate the sperm quality of F1 generation males.

Acute Toxicity of Clethodim, Cypermethrin and 2,4-D-butylate to the Larva of Chironomus sinicus

[Objective] The aim of this study was to detect the acute toxicity of clethodim, cypermethrin and 2,4-D-butylate. [Method] Chironomus sinicus larvae were exposed to different concentrations of clethodim, cypermethrin and 2,4-D-butylate. Survival rate, lethal concentration 50 （LC50） and superoxide dismutase （SOD） activity in the homogenate of the larvae were monitored to detect the toxicity of the pesti- cides. [Result] The survival rates of C. sinicus larvae exposed to cypermethrin and 2,4-D-butylate for 12 h were almost unchanged at different concentrations, but de- creased with concentration increasing 48 h later. For each pesticide, the differences in survival rates of C. sinicus larvae at 48 h were significant. The 48 h LC50 of clethodim, cypermethrin and 2,4-D-butylate to C. sinicus larvae were 1.842, 0.150 and 1.999 mg/L, respectively. The acute toxicity of cypermethrin was the highest a- mong the three pesticides and that of 2,4-D-butylate was the lowest. Clethodim sig- nificantly reduced the SOD content in a dose-dependent manner. 2,4-D-butylate also reduced SOD content in C. sinicus larvae, but the reduction was not significantly re- lated to its dosage. However, cypermethrin showed no significant effect on SOD ac- tivity in C. sinicus larvae.

Heteropolyacids Catalysis in Synthesizing Butylacrylate

The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl acrylate are reported. It has been demonstrated that 12 tungstophosphoric acid is the most effective catalyst among more than 20 HPA(salts). Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of alcohol to acid is 1.2∶1.0 , the catalyst concentration 1%(mass fraction), the reaction time 2 h, the temperature 98—124 ℃ and a certain amount of polymerization inhibitor exists.

Chlorinated butyl rubber/two-step modified montmorillonite nanocomposites:Mechanical and damping properties

Montmorillonite(MMT) was modified by ultrasound and castor oil quaternary ammonium salt intercalation method to prepare a new type of organic montmorillonite(OMMT). The surface structure, particle morphology, interlayer distance, and thermal behavior of the samples obtained were characterized. The modified OMMT was then added to chlorinated butyl rubber(CIIR) by mechanical blending, and a composite material with excellent damping properties was obtained. The mechanical experiment results of CIIR nanocomposites showed that the addition of OMMT improved their tensile strength, hardness,and stress relaxation rate. Compared with pure CIIR, when the content of OMMT was 5 phr(part per hundred of rubber), the tensile strength of the nanocomposite was increased by 677% and the elongation at break was also increased by 105.4%. The enhancement of this performance was mainly due to the dispersion of the nanosheets in CIIR rubber and the chemical interaction between the organoclay and the polymer matrix, which was confirmed by morphology and spectral analysis. OMMT also endowed a positive effect on the damping properties of CIIR nanocomposites. After adding 5 phr of OMMT, the nanocomposite owned the best damping performance, and the damping factor, tanδmax, was 37.9% higher than that of pure CIIR. Therefore, the good damping and mechanical properties of these CIIR nanocomposites provided some novel and promising methods for preparing high-damping rubber in a wide temperature range.

Adsorption kinetics and thermodynamics of sodium butyl xanthate onto bornite in flotation

In this paper,the effect of sodium butyl xanthate(NaBX)adsorption on the surface of bornite at different pH on flotation was studied by adsorption kinetic and thermodynamic.The flotation results demonstrated that the recovery was the highest when pH was 9 in NaBX solution(4×10^?5 mol/L).The adsorption kinetics showed the reaction of NaBX on the bornite conformed to the second order kinetic equation;it belonged to the multimolecular layer adsorption of Freundlich model;the maximum adsorption rate constant was 0.30 g/(10^?6 mol·min),and the equilibrium adsorption capacity was 2.70×10^?6 mol/g.Thermodynamic calculation results indicated that the adsorption process was spontaneous chemisorption,and the adsorption products of NaBX on bornite surface were cupric butyl xanthate,ferric butyl xanthate and dixanthogen,which were confirmed by infrared spectrum measurements.

Preparation of Butyl Chloride from Butanol and Hydrochloric Acid Using Ionic Liquids as Catalyst

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst （ZnCl2）. The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate （[BMIM][BF4]） and N-butyl-N-methylimidazolium chloride （[BMIM]Cl） as well as hydrochloric salts of N-methylimidazol （[HMIM]Cl）, pyridine （[HPy]Cl） and triethylamine （[HEt3N]Cl）. It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt3N]Cl is slightly superior to ZnCl2, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.

Preparation of NH_4ZrH(PO_4)_2·H_2O via solid-state reaction at low heat and its catalytic performance in the synthesis of butyl acetate

Nanocrystalline NH4ZrH（PO4）2·H2O was obtained by grinding ZrOC12·8H2O and （NH4）2HPO4 in the presence of surfactant PEG-400 via solid-state reaction at room temperature. The product NH4ZrH（PO4）2·H2O and its product of thermal decomposition were characterized using thermogravimetry and differential thermal analyses （TG/DTA）, Fourier transform infrared spectroscopy （FT-IR）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. Nanocrystalline NHaZrH（PO4）2·H2O with an average particle size of 17 nm was obtained when the product was kept at80℃ for 3 h. Its crystalline framework was stable at temperatures below 250℃. In addition, the catalytic performance of NH4ZrH（PO4）2·H2O in the synthesis of butyl acetate was investigated. The results show that NH4ZrH（PO4）2·H2O behaved as an excellent heterogeneous catalyst in the synthesis of butyl acetate.

Dietary Exposure to Benzyl Butyl Phthalate in China

Objective Benzyl butyl phthalate （BBP） is a plasticizer used in food contact materials. Dietary exposure to BBP might lead to reproduction and developmental damages to human. The present paper was aimed to assess the health risk of BBP dietary exposure in Chinese population. Methods The BBP contents were detected in 7409 food samples from 25 food categories by gas chromatography-mass spectrometry operated in selected ion monitoring （SIM） mode. The dietary exposures of BBP in different age and sex groups were estimated by combining the content data with food consumption data derived from 2002 China National Nutrient and Health Survey, and evaluated according to the tolerable daily intake （TDI） of BBP established by European Food safety Agency. Results It was found that BBP was undetectable in most samples and the highest level was 2.69 mg/kg detected in a vegetable oil sample. The average dietary exposure of BBP in people aged 〉2 years was 2.03μg/kg bw per day and the highest average exposure was found in 2-6 years old children （1.98μg/kg bw per day）. The BBP exposure in 7-12 months old children excessed 10% of tolerable daily intake （TDI） in worst scenario. Conclusion The health risk of BBP dietary exposure in Chinese population is low and, considering BBP alone, there is no safety concern.