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Relationship between polymerization degree and cementitious activity of iron ore tailings 被引量:2
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作者 Zhong-lai Yi Heng-hu Sun +2 位作者 Chao Li Yin-ming Sun Yu Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2010年第1期116-120,共5页
The aim of this study is to understand the relationship between the polymerization degree and cememitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan... The aim of this study is to understand the relationship between the polymerization degree and cememitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan were studied in terms of their ability to become cementitious materials. Compound thermal activation was used to improve the cementitious properties of the tailings, while analyzing methods, such as X-ray diffraction (XRD), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectrometer (XPS), were employed to study the changes in phase and structure under different activation conditions. The results reveal clear relationships between the binding energies of Si2p and O 1 s, polymerization degree, and cementitious activity of iron ore tailings. 展开更多
关键词 iron ore tailing polymerization degree cementitious activity thermal activation
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Preparation of Polystyrenylphosphonous Acid of Low Polymerization Degree and Influence of Initiators upon the Free Radical Reaction Mechanism 被引量:2
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作者 XiangKaiFU YanSUI 《Chinese Chemical Letters》 SCIE CAS CSCD 2002年第3期219-222,共4页
The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initia... The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, there are 2 or 3 series of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH (C6H5)]n-PO2H2 respectively. 展开更多
关键词 Polystyrenylphosphonous acid (PSPA) low polymerization degree 2 2-azobisiso-butyronitrile (AIBN) benzoyl peroxide (BPO) reaction mechanism.
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Variation in Polymerization Degree of C-A-S-H Gels and Its Role in Strength Development of Alkali-activated Slag Binders 被引量:1
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作者 LIU Qing ZHANG Jiakang +1 位作者 SU Yuewei LÜ Xianjun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2021年第6期871-879,共9页
To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration p... To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration products,degree of hydration of the slag,and the degree of polymerization of C-A-S-H gels of binders were examined.The experimental results indicate that the pH of the pore solution increased with an increase in the Na_(2)O concentration.However,mortar with an optimum compressive strength value of 81.0 MPa at 28 d was obtained when water glass modulus was 1.5.The main hydration product is a C-A-S-H gel for which the quantity and the degree of polymerization depend strongly on the Na_(2)O concentration;for a given range,both increase with increasing Na_(2)O concentration,thus yielding an enhanced strength.A further increase in the Na_(2)O concentration continuously increases the quantity of C-A-S-H gels while drastically reducing the degree of polymerization.The positive effect of the former is counteracted by the adverse effect of the latter,ultimately,leading to a decreased strength.Furthermore,we reveal that the degree of polymerization for C-A-S-H gels may be affected by pH,through a series of complex chemical reactions. 展开更多
关键词 Na_(2)O concentration compressive strength C-A-S-H gels degree of hydration degree of polymerization
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The Research of Connection between Degree of Polymerization and Frequency Domain Dielectric Spectroscopy Characteristics during Oil-Paper Insulation Aging
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作者 Danyu Jiang Guangning Wu +1 位作者 Xian Yang Qingkai Hao 《Energy and Power Engineering》 2017年第4期667-674,共8页
In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oi... In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oil-paper insulation is set up. Complex permittivity of oil-paper insulation respectively composed by new or aged oil and insulation paper with different DP are tested, and complex permittivity of oil-paper insulation respectively composed by insulation respectively composed by new oil and insulation paper with different DP and low or high moisture content are tested. The test results are analyzed, and the analysis results show that the degree of polymerization of insulation paper has an influence on complex permittivity of oil-paper insulation though influencing the distribution of moisture and acids between oil and paper. 展开更多
关键词 degree of polymerization Oil-Paper INSULATION Frequency DOMAIN Dielectric Spectroscopy MOISTURE
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Relation between the permeability and the degree of coil overlap of polymer in the bulk state
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作者 Quan Fu An Jin Wen Qian +2 位作者 Meng Wang Yin Lu Phillip Choi 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第11期1423-1426,共4页
Based on the expression of the index of coil interpenetration (i.e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory... Based on the expression of the index of coil interpenetration (i.e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory's intrinsic viscosity equation at them conditions. The ξb ofpoly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined. The permeability, permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed. 展开更多
关键词 degree of coil overlap PERMEABILITY Dense polymer membranes
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A SYNTHETIC APPROACH FOR WATER SOLUBLE HYPERBRANCHED POLY(N,N-ETHYLIDENEBIS(N-2-CHLOROACETYL ACRYLAMIDE)) WITH HIGH DEGREE OF BRANCHING VIA ATOM TRANSFER RADICAL POLYMERIZATION/SELF-CONDENSING VINYL POLYMERIZATION 被引量:1
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作者 Li-bin Bai Rong-rong Zheng +3 位作者 Wen-liang Li Yong-gang Wu 巴信武 Hai-jun Wang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2013年第7期1038-1045,共8页
A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form wa... A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form water-soluble hyperbranched poly(N,N-ethylidene bis(N-2-chloroacetyl acrylamide))s (HPECA) through atom transfer radical polymerization/self-condensing vinyl polymerization method in the presence alkyl chlorine/CuCl/2,2-bipyridine activation system which can effectively suppress the gelation formation.1H-NMR spectra and dual detector size exclusion chromatography proved the hyperbranched structure indisputably, and the degree of branching was determined by the detailed analyses of 1H-NMR spectra. The trend of the degree of branching was in consistent with the result of Mark- Houwink exponent a. The experiment results suggested that the conversion was 67%, Mw = 13.2 x 104, Mark-Houwink a = 0.282 and the degree of branching = 64% when the reaction temperature was 120 ℃, reaction time = 168 h and N,N- ethylidene bis(N-2-chloroacetyl acrylamide):Cu(I) = 50:0.62. 展开更多
关键词 Hyperbranched polymers Self-condensing vinyl polymerization Atom transfer radical polymerization High degree of branching Water soluble.
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Ceiling Degree of Polymerization for Brush Polymers Prepared via ROMP of Poly(tert-Butyl Acrylate) Macromonomers 被引量:1
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作者 QIAO Yaping YUAN Xiaoyan +1 位作者 ZHAO Yunhui REN Lixia 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2018年第5期828-832,共5页
Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesiz... Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesized via atom transfer radical polymerization in three different molecular weights, 2000(NB-PtBA-2k), 3000(NB-PtBA-3k), and 8000(NB-PtBA-8k). Additionally, brush polymers with PtBA as side chains were synthesized via ring-opening metathesis polymerization(ROMP). Kinetic studies on ROMP of NB-PtBA showed that there was a ceiling degree of polymerization(CDP) for the brush polymers, beyond which the polymerization of NB-PtBA was out of control. For brush polymers of P[NB-PtBA-2k] and P[NB-PtBA-3k], CDPs were estimated to be ca. 400, but the value of P[NB-PtBA-8k] was ca. 100. Therefore, the controlled ROMP of brush polymers was critical at the CDP limit with increased macromonomer molecular weight. 展开更多
关键词 Ring-opening metathesis polymerization MACROMONOMER Brush polymer Ceiling degree of polymeriza- tion Kinetics study
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Regulation on polymerization degree and surface feature in graphitic carbon nitride towards efficient photocatalytic H2 evolution under visible-light irradiation 被引量:1
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作者 Cheng Cheng Chung-Li Dong +5 位作者 Jinwen Shi Liuhao Mao Yu-Cheng Huang Xing Kang Shichao Zong Shaohua Shen 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第3期160-168,共9页
A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicar... A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic carbon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facilitated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H;evolution kinetics. In addition, the extended π-conjugated electronic system promoted the separation and migration of photogenerated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C–N interactions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H;production activity,the AQY achieved 36.4% at 425 nm. 展开更多
关键词 degree of polymerization Graphitic carbon nitride PHOTOCATALYSIS Solar energy HYDROGEN
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含生活垃圾焚烧炉渣的碱矿渣水泥耐高温机理
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作者 张彬彬 马宇 +2 位作者 梁咏宁 林毅武 季韬 《福州大学学报(自然科学版)》 CAS 北大核心 2024年第3期299-306,共8页
为探究生活垃圾焚烧炉渣(MSWI-BA)对碱矿渣净浆耐高温性能的影响机理,将6%的矿渣等质量替换为MSWI-BA,制备碱矿渣水泥净浆(AASBp),研究不同温度对AASBp的质量损失率、干燥收缩率和强度的影响.以普通硅酸盐水泥净浆作为对照组,结合多种... 为探究生活垃圾焚烧炉渣(MSWI-BA)对碱矿渣净浆耐高温性能的影响机理,将6%的矿渣等质量替换为MSWI-BA,制备碱矿渣水泥净浆(AASBp),研究不同温度对AASBp的质量损失率、干燥收缩率和强度的影响.以普通硅酸盐水泥净浆作为对照组,结合多种微观手段,揭示AASBp的耐高温机理,并与未掺MSWI-BA的碱矿渣水泥(AASp)进行对比.结果表明:随着温度的升高,AASBp中水化硅铝酸钙的钙硅比(C/S)先降低后升高;在400℃时,水化硅铝酸钙的聚合度最高,C/S最低;Al—O键在600℃断裂,而Si—O键在1000℃断裂;MSWI-BA可提高基体孔隙的连通性,高温处理后孔隙压力得到释放,因此AASBp比AASp具有更高的归一化抗压强度和耐高温性能. 展开更多
关键词 碱激发矿渣 生活垃圾焚烧炉渣 耐高温 干燥收缩率 水化硅铝酸钙的聚合度
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聚对苯二甲酸乙二醇酯逐步聚合工艺的模拟
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作者 郭英洁 谷志伟 +5 位作者 康宏玲 刘一男 张逸然 刘旭 王晓蓉 周世嘉 《当代化工》 CAS 2024年第6期1481-1485,共5页
聚对苯二甲酸乙二醇酯(PET)是热塑性聚酯中最常用的一类,具有良好的力学性能、耐磨性、耐热性、尺寸稳定性等。基于杜邦公司的“三釜”工艺,设计了由3个反应釜和2个分离器组成的带有循环生产的PET模拟流程,并进行了对苯二甲酸(TPA)/乙二... 聚对苯二甲酸乙二醇酯(PET)是热塑性聚酯中最常用的一类,具有良好的力学性能、耐磨性、耐热性、尺寸稳定性等。基于杜邦公司的“三釜”工艺,设计了由3个反应釜和2个分离器组成的带有循环生产的PET模拟流程,并进行了对苯二甲酸(TPA)/乙二醇(EG)进料量、酯化釜内部压力与温度以及酯化釜/终聚釜停留时间对产品聚合度和分子量的影响分析。结果表明:若要得到高聚合度的PET,应该使用多个反应釜串联的方式;在流程中,由于循环的存在,选择TPA与EG的进料质量比为2.54∶1,压力为1.013~202.650 kPa,最优操作温度为260~280℃;在实际生产中,初期应该使用较高的压力,之后逐级降低反应压力,形成一定的差压;在反应初期应尽量降低反应温度,到了反应中后期,可逐级提升反应温度;延长体系在终聚釜中的停留时间,可大幅度提高产品的聚合度。此结果可为下一步工业优化生产提供可靠的模型基础。 展开更多
关键词 PET 反应釜 Aspen plus 聚合度
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高炉渣化学组分对硅酸盐微观聚合结构演变规律的影响
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作者 冯浩明 彭程 +2 位作者 刘吉辉 孔维国 吕楠 《有色金属工程》 CAS 北大核心 2024年第9期77-85,共9页
高炉渣组分间的协同作用直接影响阴离子聚合结构的形成及复杂程度。研究了不同R_(2)、ω(MgO)/ω(Al_(2)O_(3))及ω(Al_(2)O_(3))变化时硅酸盐聚合结构的演变规律。通过热力学计算确定实验升温制度及中断的温度节点,根据拉曼光谱分析发... 高炉渣组分间的协同作用直接影响阴离子聚合结构的形成及复杂程度。研究了不同R_(2)、ω(MgO)/ω(Al_(2)O_(3))及ω(Al_(2)O_(3))变化时硅酸盐聚合结构的演变规律。通过热力学计算确定实验升温制度及中断的温度节点,根据拉曼光谱分析发现当R_(2)和ω(MgO)/ω(Al_(2)O_(3))增加时,高炉渣中的硅酸盐阴离子团发生解聚,呈现Q_(4)、Q_(3)向Q_(0)、Q_(1)和Q_(2)结构单元演变,导致结构稳定性变差,炉渣流动性增强,当碱度大于1.2时,ω(MgO)/ω(Al_(2)O_(3))大于0.55时则出现反向转化或变缓趋势。随ω(Al_(2)O_(3))的增加,Q_(0)相对含量变化幅度不大,Q_(1)相对含量先增加后减少,Q_(2)相对含量明显减少,Q_(3)相对含量明显增加,Q_(4)相对含量整体呈增加趋势,炉渣阴离子团结构趋于复杂,渣系中的非桥氧含量呈现缓慢的降低趋势,当ω(Al_(2)O_(3))含量超过16%时,非桥氧含量下降趋势则更为明显。 展开更多
关键词 高炉渣 硅酸盐结构单元 聚合度 非桥氧
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绝缘纸在矿物油与菜籽油基天然酯中的加速热老化特性分析
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作者 李欢欢 王思裕 +4 位作者 余武锟 刘博睿 周文豪 郑怀 关焕梅 《绝缘材料》 CAS 北大核心 2024年第4期44-48,共5页
天然酯较矿物绝缘油具有燃点高、可降解性好并且能延缓绝缘纸热老化速率等优点,作为提升变压器寿命或短时过载能力的液体绝缘介质正受到广泛关注。本文选取我国食用油中占比较大的菜籽油作为基油制备天然酯绝缘液,通过试验比较不同含水... 天然酯较矿物绝缘油具有燃点高、可降解性好并且能延缓绝缘纸热老化速率等优点,作为提升变压器寿命或短时过载能力的液体绝缘介质正受到广泛关注。本文选取我国食用油中占比较大的菜籽油作为基油制备天然酯绝缘液,通过试验比较不同含水量绝缘纸在菜籽油基天然酯和矿物油中的加速热老化特性,并研究了氧气对绝缘纸在两种不同绝缘液中的加速热老化特性的影响。结果表明:在相同温度下,含水量是影响绝缘纸热老化速率的主要因素,氧气会降低菜籽油基天然酯对低含水量绝缘纸热老化速率的抑制作用。结合绝缘纸在绝缘液热老化过程中比强度与聚合度的实测数据,导出得到考虑含水量和氧气影响的绝缘纸纤维素分解反应数学模型,应用该模型可以对绝缘纸在绝缘液中的热老化过程和寿命进行预测。 展开更多
关键词 菜籽油基天然酯 加速热老化 含水量 比强度 聚合度
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转酯化法制备芦苇基醋酸纤维素的工艺研究
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作者 唐海哲 周衡书 +1 位作者 徐奕 徐国强 《针织工业》 北大核心 2024年第7期23-26,共4页
以芦苇纤维素为原材料,在以1,8-二氮杂二环十一碳-7-烯(DBU)为催化剂,醋酸异丙烯酯(IPA)或乙酸乙烯酯(VA)为乙酰化试剂,二甲基亚砜(DMSO)为溶剂的条件下,对芦苇纤维素进行转酯化反应制备芦苇基醋酸纤维素。探讨了不同试验条件对芦苇基... 以芦苇纤维素为原材料,在以1,8-二氮杂二环十一碳-7-烯(DBU)为催化剂,醋酸异丙烯酯(IPA)或乙酸乙烯酯(VA)为乙酰化试剂,二甲基亚砜(DMSO)为溶剂的条件下,对芦苇纤维素进行转酯化反应制备芦苇基醋酸纤维素。探讨了不同试验条件对芦苇基醋酸纤维素聚合度及取代度的影响,并通过聚合度测定、酸碱滴定取代度测定及红外光谱分析等手段进行表征。结果表明,在以IPA作为乙酰化试剂,DMSO作为溶剂,DBU作为催化剂,反应时间为4.5 h,反应温度为110℃时所制备的芦苇基醋酸纤维素最佳;所制芦苇基二醋酸纤维素的聚合度可达483.63,取代度可达2.41。 展开更多
关键词 芦苇 醋酸纤维素 转酯化法 聚合度 取代度
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Using 2D NMR to determine the degree of branching of complicated hyperbranched polymers 被引量:3
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作者 ZHU XinYuan CHEN Liang +1 位作者 CHEN Yan YAN DeYue 《Science China Chemistry》 SCIE EI CAS 2008年第11期1057-1065,共9页
Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, ... Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, intricate structure and severe overlap of spectral signals hinder the determina-tion of DB using traditional methods. In this work, the architecture of complicated hyperbranched polymers has been elucidated with the help of 2D NMR techniques. Using such a method, overlapped NMR signals can be well separated into a two-dimensional space, and additional structural information is also available. Correspondingly, quantitative analysis for complicated systems can be realized. De-termination of DBs for three types of complicated hyperbranched polymers synthesized from step-polymerization, self-condensation vinyl polymerization and self-condensation ring-opening po-lymerization is shown as examples. 展开更多
关键词 HYPERBRANCHED polymer degree of branching 2D NMR
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纳米丁腈橡胶胶乳的制备与催化加氢
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作者 李文鑫 张宝嘉 +2 位作者 周骏阳 宋建晖 王辉 《合成橡胶工业》 CAS 2024年第5期394-397,共4页
采用常规乳液聚合法结合低温间歇聚合工艺制备了丁腈橡胶胶乳,使用自制钌系催化剂对该胶乳进行乳液加氢,系统研究了催化剂用量和氢气压力对丁腈橡胶胶乳加氢效果的影响规律。结果表明,所制备丁腈橡胶胶乳的平均粒径为69.13 nm,加氢前后... 采用常规乳液聚合法结合低温间歇聚合工艺制备了丁腈橡胶胶乳,使用自制钌系催化剂对该胶乳进行乳液加氢,系统研究了催化剂用量和氢气压力对丁腈橡胶胶乳加氢效果的影响规律。结果表明,所制备丁腈橡胶胶乳的平均粒径为69.13 nm,加氢前后胶乳的粒径基本保持不变且胶乳稳定性良好;氢气压力越大催化加氢效果越好;当催化剂质量分数为0.017 5%时,可制得氢化度为99%以上且不含凝胶的产品。 展开更多
关键词 丁腈橡胶胶乳 乳液聚合 加氢 钌系催化剂 粒径 氢化度 凝胶含量
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纤维素甲酸酯的制备及应用研究进展
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作者 曹宇翔 吴美燕 +1 位作者 刘莹莹 李滨 《天津造纸》 2024年第2期1-12,共12页
纤维素酯是一类重要的纤维素衍生物,在纺织、食品、包装、电子、医药、化工和军工等领域应用广泛。甲酸可以与纤维素表面的羟基发生酯化反应,在纤维素表面引入酯基,生成纤维素甲酸酯。本文综述了纤维素甲酸酯的制备工艺及其在聚合物加... 纤维素酯是一类重要的纤维素衍生物,在纺织、食品、包装、电子、医药、化工和军工等领域应用广泛。甲酸可以与纤维素表面的羟基发生酯化反应,在纤维素表面引入酯基,生成纤维素甲酸酯。本文综述了纤维素甲酸酯的制备工艺及其在聚合物加填、皮克林乳液、功能性薄膜、丝线等领域的应用,以期为纤维素甲酸酯未来的规模化制备和应用提供借鉴。纤维素甲酸酯的制备将朝着绿色、低能耗的方向发展;其应用将更加多元化,特别是在开发高质量、可持续材料以及利用其进一步衍生化制备功能性材料方面具有广阔的研究前景。 展开更多
关键词 纤维素酯 纤维素甲酸酯 取代度(DS) 聚合度(DP)
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棉秆韧皮浆粕的制备与性能测试
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作者 汪烨 林燕萍 杨陈 《河南工程学院学报(自然科学版)》 2024年第1期7-11,共5页
通过高温蒸煮和有机酸与乙醇组合溶解方式对棉秆韧皮进行制浆,并以浆粕得率为依据进行工艺优化。用核磁共振、红外光谱和热重分析等技术对制浆前棉秆韧皮和制浆所得浆粕的聚合度、相对分子量、Iα纤维素含量、分子结构和热学性能等指标... 通过高温蒸煮和有机酸与乙醇组合溶解方式对棉秆韧皮进行制浆,并以浆粕得率为依据进行工艺优化。用核磁共振、红外光谱和热重分析等技术对制浆前棉秆韧皮和制浆所得浆粕的聚合度、相对分子量、Iα纤维素含量、分子结构和热学性能等指标进行表征。结果表明:棉秆韧皮制浆的最佳工艺为温度100℃、处理时间120 min、过氧化氢质量分数10%、乙醇质量分数60%;经制浆处理,棉秆韧皮中的木质素和半纤维素发生了部分酯化和酰化,使得其中的Iβ纤维素和微纤维结构受到破坏,热学性能下降,Iα纤维素含量增加。 展开更多
关键词 棉秆韧皮 浆粕 聚合度 分子量 红外光谱 核磁共振 热学性能
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当前肥料市场不同短链聚磷酸盐肥料关键性状之比较
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作者 亢龙飞 徐琳峰 +2 位作者 王诗荣 江诚涛 褚贵新 《浙江农业学报》 CSCD 北大核心 2024年第5期1134-1143,共10页
目前,市场所售的聚磷酸盐肥料质量参差不齐。该研究从全国肥料市场收集10种具有代表性的聚磷酸盐肥料,测定其总氮、总磷(以P2O5计)含量,及聚合度、聚合率和溶解度等指标,采用层次聚类方法和Mantel检验进行比较。结果显示,样品肥料的平... 目前,市场所售的聚磷酸盐肥料质量参差不齐。该研究从全国肥料市场收集10种具有代表性的聚磷酸盐肥料,测定其总氮、总磷(以P2O5计)含量,及聚合度、聚合率和溶解度等指标,采用层次聚类方法和Mantel检验进行比较。结果显示,样品肥料的平均聚合度为4.00,测定值与标注值的平均偏差为6.38%;平均聚合率为83.8%,测定值与标注值的平均偏差为2.59%;总氮含量在8.6%~28.7%,测定值与标注值的平均偏差为2.59%;总磷含量在18.0%~64.2%。Mantel检验结果显示,总氮含量、总磷含量、酸碱度和盐分指数与肥料的聚合率有显著(P<0.05)关联,总磷含量、溶解度、盐分指数、缩二脲含量与聚合度有显著关联。结果表明,不同聚磷酸盐肥料的性质差异显著,且部分肥料指标的测定值与标注值之间具有明显差异。不同肥料生产单位亟须统一指标测定体系,以便提供精准、全面的商品信息。 展开更多
关键词 聚磷酸盐肥料 溶解度 聚合度 聚合率 磷肥
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聚合瓷修复体对前牙修复患者咀嚼功能、牙体敏感程度的作用效果及其影响因素分析 被引量:1
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作者 董腾姣 《华北理工大学学报(医学版)》 2024年第1期34-38,共5页
目的分析Ceramage聚合瓷修复体对前牙修复患者咀嚼功能、牙体敏感程度的作用效果及其影响因素。方法选取2020年5月~2022年4月于我院进行前牙修复的102例前牙冠折断患者为研究对象,均采用Ceramage聚合瓷修复体进行修复,观察患者咀嚼功能... 目的分析Ceramage聚合瓷修复体对前牙修复患者咀嚼功能、牙体敏感程度的作用效果及其影响因素。方法选取2020年5月~2022年4月于我院进行前牙修复的102例前牙冠折断患者为研究对象,均采用Ceramage聚合瓷修复体进行修复,观察患者咀嚼功能、牙体敏感程度变化。修复后1年对患牙进行评估,根据预后情况将患者分为预后良好组和预后不佳组,收集两组临床资料,分析影响聚合瓷修复体前牙修复预后的因素。结果Ceramage聚合瓷修复体颜色、形态、边缘密合度有效率均为100%。修复后,患者咀嚼效率和最大咬合力均明显增大(P<0.05),牙齿敏感程度明显改善(P<0.05)。单因素分析显示,预后不佳组吸烟、不良卫生习惯、牙冠台阶状断端、牙菌斑控制不佳与预后良好组均存在显著差异(P<0.05)。多因素Logistic回归分析显示,不良卫生习惯、台阶状断端、牙菌斑控制不佳是患者预后的影响因素(P<0.05)。结论Ceramage聚合瓷修复体可以有效改善前牙折冠患者咀嚼功能,减轻牙体敏感程度,患者预后与不良卫生习惯、牙冠折断状态、口腔环境有关,需针对性进行预防。 展开更多
关键词 前牙修复 Ceramage聚合瓷修复体 咀嚼功能 牙体敏感程度影响因素
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The distribution of degree of crystallinity-New concept in polymer science 被引量:1
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作者 Pingsheng He 《Chinese Chemical Letters》 SCIE CAS CSCD 2018年第12期1711-1712,共2页
Due to the structure characteristics of huge macromolecular size and the very low motion feature of the polymer chain which is very difficult to arrange regularly their long chain into the three dimensional space,thus... Due to the structure characteristics of huge macromolecular size and the very low motion feature of the polymer chain which is very difficult to arrange regularly their long chain into the three dimensional space,thus the polymer will incompletely crystallize except for the macroscopic single crystal of polydiacetylene polymerized by means of solid state crystalline polymerization. 展开更多
关键词 PCL The distribution of degree of crystallinity-New concept in polymer science
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