一种无卤阻燃乙烯-醋酸乙烯酯共聚物的热分解动力学研究

通过极限氧指数法(LOI)和垂直燃烧(UL-94)测试考察了一种无卤阻燃乙烯-醋酸乙烯酯共聚物(EVA)的阻燃性能;利用热重分析法(TG)研究了纯EVA及阻燃EVA在不同升温速率下的热稳定性及热分解动力学,并采用Kissinger及Flynn-Wall-Ozawa方法计算了纯EVA和阻燃EVA的热分解表观活化能。结果表明,添加40%复合膨胀阻燃剂的EVA复合材料,极限氧指数达到28.6%,UL-94测试达到V-0级,残炭量相对纯EVA明显提高;随着升温速率增大,EVA和阻燃EVA的起始失重温度和各阶段的失重峰温均向高温方向移动;二者在第一阶段的热分解活化能均低于第二阶段,阻燃剂的添加使EVA的最大失重速率明显降低,热分解表观活化能提高,增强了材料的热稳定性和阻燃性。     

新型含磷环氧树脂的合成、固化及阻燃性能研究

基于2-甲基-2,5-二氧-1,2-氧磷杂环戊烷(OP)的环状酸酐结构和可以通过水解或醇解开环的特点,对OP/对苯二酚/环氧树脂预聚体的反应可行性、固化过程以及阻燃性能进行了研究;成功制备了含磷环氧树脂,固化12 h后的环氧树脂具有良好的阻燃性能,极限氧指数(LOI,%)为25.7%,垂直燃烧测试达到UL-94 V-0级别。     

新型磷-硅阻燃剂和聚磷酸铵对PP的协效阻燃作用

研究了一种含磷硅高分子阻燃剂(EMPZR)和聚磷酸铵(APP)对聚丙烯(PP)阻燃及力学性能的影响。当APP/EMPZR=20/15(质量比)时,所制得的阻燃PP复合材料氧指数达到28.0%,垂直燃烧达到UL-94 V-2级;与纯PP相比,拉伸、弯曲和冲击强度都没有下降;热失重分析(TGA)测试表明,阻燃PP材料在600℃时的残炭量为21.20%(质量分数),成炭率显著提高;扫描电镜(SEM)对残炭形貌的表征以及氧指数测试前后的阻燃PP材料的红外图谱分析证实了EMPZR和APP在PP中良好的协效阻燃作用。     

含磷环氧树脂的合成及阻燃研究

采用阻燃剂9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)与双酚A型环氧化物(E-51)反应,合成了含磷反应型阻燃环氧化物(E-P),在间苯二胺固化剂作用下,利用E-P制备了含磷反应型阻燃环氧树脂(EP-P). 采用傅里叶红外光谱(FTIR)和热失重分析(TGA)分别对E-P的结构及EP-P的热分解行为进行了表征;通过浸水实验,采用极限氧指数(LOI)和UL-94垂直燃烧等方法对比研究了EP-P与添加聚磷酸铵(APP 422)的添加型阻燃环氧树脂EP-AP的阻燃剂抗迁出性. 结果表明,含磷反应型阻燃环氧树脂EP-P比添加型阻燃环氧树脂EP-AP的阻燃效率高、阻燃耐久性更强.     

FRC-6和KH602共改性水性聚氨酯的制备

以大豆油基多元醇、甲苯二异氰酸酯(TDI)、二羟甲基丙酸(DMPA)为预聚体单体,引入N,N-双(2-羟乙基)氨基亚甲基膦酸二乙酯(FRC-6)作为硬链段小分子扩链剂和N-β-(氨乙基)-γ-氨丙基甲基二甲氧基硅烷(偶联剂KH602)作为后扩链剂,制备一系列阻燃型KWPU.通过扫描电镜(SEM)、热重分析(TG)、极限氧指数(LOI)、垂直燃烧测试(UL-94)表征KWPU的阻燃性能.结果表明:当FRC-6的含量不变,KH602添加量增加时,TG显示残留的焦炭率在增大,从2.70%(wt)提高到5.72%(wt).而SEM证明KH602含量越高,炭化层更连续、更致密.随KH602添加量增加,垂直燃烧UL-94由K-0的无等级到K-15的V-1等级,以及LOI值从空白样的20.9%增大到K-20的25.8%,表明KH602对膜材料的阻燃性有一定的增强作用.     

无卤反应型含磷氮阻燃剂的合成及其阻燃改性环氧树脂的研究

通过N-羟乙基苯胺、4-羟基苯甲醛、9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)反应,合成了一种反应型含磷氮阻燃剂6-((4-((2-羟乙基)氨基)苯基)(4-羟基苯基)甲基)二苯并-[1,2]-氧磷腈-6-氧化物(PNOH).以PNOH为阻燃剂与4,4'-二氨基二苯甲烷复配制得了阻燃环氧树脂PNOH/EP,并研究了PNOH添加量(质量分数)对PNOH/EP各项性能的影响.结果表明,PNOH/EP的热稳定性较好,其热分解残炭率较纯的环氧树脂有明显提高;当PNOH添加量为2.4%时,PNOH/EP的极限氧指数(LOI)大于30.0%,垂直燃烧等级为V-0级,储能模量及热稳定性有所提高;当PNOH添加量为10.0%时,PNOH/EP的LOI达到36.0%.阻燃剂PNOH含磷、氮元素,可起到无卤协同阻燃的作用,其与环氧树脂反应生成的复合材料能保持基体良好的热性能和机械性能.     

聚磷酸铵/氢氧化镁复配填充聚氨酯硬泡的阻燃性能

摘要: 为了增强聚氨酯硬泡在燃烧过程中的的阻燃性能和抑烟性能,以聚磷酸铵与氢氧化镁组成协效阻燃剂加入聚氨酯中制备了阻燃聚氨酯硬泡。通过临界氧指数测定仪、水平垂直燃烧测定仪、锥形量热仪和电子万能试验机研究了聚磷酸铵和氢氧化镁不同配比对聚氨酯泡沫塑料的阻燃性能、燃烧行为和压缩强度的影响。并用扫描电镜观察了阻燃材料燃烧后残炭的微观结构。结果表明,加入30份聚磷酸铵和10份氢氧化镁的聚氨酯硬泡的氧指数达27.5%,最大热释放速率为113.5 KW/m2,比纯聚氨酯硬泡的最大热释放速率下降了22.3%,最大烟释放速率下降58.9%。成炭致密,有良好的阻燃效果。证明复合阻燃剂加入能够增强聚氨酯材料的阻燃抑烟性能。     

一种二茂铁基含磷阻燃剂在膨胀型聚丙烯中的应用

以二茂铁基聚合物(PFDCHQ)和膨胀型阻燃剂(IFR)对聚丙烯(PP)进行阻燃改性,通过极限氧指数(LOI)和垂直燃烧(UL-94)测试研究了PP和PP/IFR/PFDCHQ复合材料的燃烧行为,并通过热重分析(TGA)研究了它们的热稳定性,结果表明,PFDCHQ的加入可以提高PP/IFR体系的阻燃性能和热稳定性。对UL-94测试后的残炭进行Raman光谱和扫描电子显微镜(SEM)测试,表明PP 76/IFR 23. 5/PFDCHQ 0. 5(PP-2)和PP 76/IFR 23/PFDCHQ 1(PP-3)复合材料能够形成石墨化程度高、连续且致密的炭层,说明PFDCHQ与IFR之间具有很好的协效阻燃作用。     

基于聚磷酸铵的乙烯基酯树脂的阻燃机理研究

乙烯基酯树脂(VER)因其具有良好耐腐蚀性能和优异的物理性能被广泛应用于诸多领域，然而由于VER极易燃，限制了其使用范围.为了提高VER的阻燃性，本文将聚磷酸铵(APP)作为阻燃剂引入VER中，制备得到阻燃乙烯基酯树脂固化物；采用热重分析仪(TGA)表征了VER的热稳定性；扫描电子显微镜(SEM、SEM-EDX)研究了VER燃烧后残炭的微观形貌，表面元素组成及分布；利用极限氧指数(LOI)、垂直燃烧测试(UL-94)、锥形量热(CCT)对其阻燃性能进行测试；采用热重红外光谱联用仪(TG-FTIR)等手段分析APP在VER中的阻燃机理.研究结果表明，当APP的引入量为30 wt%时，乙烯基酯树脂的极限氧指数达到30.3%,通过UL-94 V-0级别. APP在凝聚相和气相中共同发挥阻燃作用.     

一种新型聚合型磷硅阻燃剂对环氧树脂阻燃性能的影响

以10-(2,5-二羟基苯基)-9,10-二氢-9-氧杂-10-膦菲-10-氧化物(ODOPB)和甲基乙烯基二氯硅烷(DCMVS)为原料,咪唑为缚酸剂合成了一种新型聚合型磷硅阻燃剂,聚2-(9,10-二氢-9-氧杂-10-膦菲-10-氧化物)-1,4-二苯氧基-甲基乙烯基硅醚(PODOPBVS),并通过熔融共混制备了环氧树脂(EP)/PODOPBVS阻燃复合材料。通过热重分析(TGA)、氧指数值(LOI)和垂直燃烧测试(UL-94)研究了不同PODOPBVS添加量对复合材料热性能和阻燃性能的影响。实验结果表明,当PODOPBVS添加量(质量分数)为7%(EP7)时,EP复合材料的残炭率达14.74%,LOI可达28.5%,UL-94达到V-0级,通过锥型量热测试发现,与纯EP相比较,EP7最大热释放速率下降了约52%,残炭提高了约119%。     

新型含氟含磷水性聚氨酯的合成及在棉织物上的应用

由单体3,3-双(三氟乙氧基)甲基氧杂环丁烷(BFOx)和3,3-双(叠氮甲基)氧杂环丁烷(BAMO)阳离子开环共聚而制得的含氟聚醚二醇,与炔丙氧基磷酸二乙酯(DEPP)发生"Click"反应,将磷酸酯结构以侧链的形式嫁接于含氟聚醚二醇的链上.这种含氟含磷聚醚二醇作为水性聚氨酯APU的软段部分,通过与异佛尔酮二异氰酸酯(IPDI)聚合而得到阴离子水性聚氨酯(APU)乳液.经该乳液整理后的棉织物,其表面具有拒水性能,对水的接触角可达到135°,织物的极限氧指数(LOI)达到19.5%.     

Kinetics of thermal decomposition of hydrated minerals associated with hematite ore in a fluidized bed reactor

The kinetics of removal of loss on ignition (LOI) by thermal decomposition of hydrated minerals present in natural iron ores (i.e., kaolinite, gibbsite, and goethite) was investigated in a laboratory-scale vertical fluidized bed reactor (FBR) using isothermal methods of kinetic analysis. Experiments in the FBR in batch processes were carried out at different temperatures (300 to 1200℃) and residence time (1 to 30 min) for four different iron ore samples with various LOIs (2.34wt% to 9.83wt%). The operating velocity was maintained in the range from 1.2 to 1.4 times the minimum fluidization velocity (U_mf). We observed that, below a certain critical temperature, the FBR did not effectively reduce the LOI to a desired level even with increased residence time. The results of this study indicate that the LOI level could be reduced by 90% within 1 min of residence time at 1100℃. The kinetics for low-LOI samples (<6wt%) indicates two different reaction mechanisms in two temperature regimes. At lower temperatures (300 to 700℃), the kinetics is characterized by a lower activation energy (diffusion-controlled physical moisture removal), followed by a higher activation energy (chemically controlled removal of LOI). In the case of high-LOI samples, three different kinetics mechanisms prevail at different temperature regimes. At temperature up to 450℃, diffusion kinetics prevails (removal of physical moisture); at temperature from 450 to 650℃, chemical kinetics dominates during removal of matrix moisture. At temperatures greater than 650℃, nucleation and growth begins to influence the rate of removal of LOI.     

Flame Retardancy and Thermal Property of Poly (ethylene terephthalate)/Modified Cyclotriphosphazene Composites

In this study,hexachlorocyclotriphosphazene( HCCP)modified by boric acid and 3-aminopropyltriethoxysilane( KH-550)in solvent diglyme( FR-HCCP) was used as the flame retardant for poly( ethylene terephthalate)( PET) composites. The flame retardancy and thermal property of pure PET and flame-retarded PET composites were mainly investigated. The flame retardancy was investigated by limited oxygen index( LOI) and UL-94 vertical burning test. The results showed that the composites could achieved an increased UL-94 V-0 rating and LOI value 30. 2, when the content of FR-HCCP was just 1%. The pyrolysis-gas chromatography-mass spectrometry( Py-GC / MS) study demonstrated that introducing FR-HCCP into PET would prevent the polymer pyrolysis during heating. TGA analysis showed that the addition of FR-HCCP could improve the char formation of the system. Roman spectra showed the order degree of residue was increasing by adding the additive. The morphology and the chemical structure of the charred residue were detected by SEMand FTIR,respectively. Results demonstrated that a good barrier was formed by the char of the composite,which protected the inside of the composite during burning.     

阻燃剂DDPA的合成及在环氧树脂中的应用研究

一锅法合成了一种磷杂菲类阻燃剂2-((9,10-二氢-9-氧杂-10-磷杂菲-10-基)(苯基)甲基)氨基-9',10'-蒽醌(DDPA),采用红外光谱和核磁共振确定了阻燃剂DDPA的分子结构,并将其用于阻燃改性环氧树脂.通过悬臂梁冲击试验机、电子万能力学试验机、热重分析仪(TGA)、差示扫描量热仪(DSC)、氧指数仪...     

Characterization of a FeMo cofactor-deficient MoFe protein from a nifE-deleted strain （DJ35） of Azotobacter vinelandii

A MoFe protein （△nifE Av1） with a purity of ～80% was purified from a nifE-deleted mutant of Azotobacter vinelandii DJ35. Compared with MoFe protein purified from wild-type strain OP （OP Av1）, △nifE Av1 had the same subunits composition, and had immune reaction with antibody to OP Av1, but its relative mobility in anaerobic native polyacrylamide gel electrophoresis （PAGE） was a little larger than that of OP Av1. Metal analysis showed that Mo and Fe contents of △nifE Av1 both apparently decreased. When complemented with OP Fe protein, △nifE Av1 had no C2H2-reduction activity, but it could be in vitro activated by FeMoco extracted from OP Av1. The circular dichroism （CD） spectrum of △nifE Av1 at ～450 nm was similar to that of OP Av1, while the EPR signal at g≈3.7 was absolutely silent, and the signal intensities at g≈4.3 and 2.0 decreased by 75% and 50%, respectively. The results indicated that △nifE Av1 purified from DJ35 was a FeMoco-deficient but P-cluster-containing MoFe protein.     

钛、锆化合物对羊毛纤维性能的影响

用钛、锆化合物同己二酸对羊毛纤维进行阻燃处理,并用热分析、剩碳率、氧指数、扫描电镜(SEM)等对所得到的阻燃羊毛纤维的热降解行为进行了研究.实验证明:经过阻燃处理的羊毛纤维热降解温度比未经处理的下降,剩碳率、氧指数和降解反应活化能升高,阻燃性能增强.     

水性环氧树脂改性水泥基材料应用于彩色路面的研究

通过水性环氧树脂改性水泥基彩色砂浆,制备一种力学性能优异且经济的彩色路面铺装材料,并通过抗折强度试验、抗压强度试验、粘结强度试验、抗滑性能试验、色彩耐久性试验研究了复合材料的最佳配合比和路用性能,通过SEM试验分析了水性环氧树脂和粉煤灰对水泥水化产物的影响。研究结果表明：粉煤灰掺量10%,水性环氧树脂掺量10%,改性砂浆力学性能最优;改性砂浆的BPN基本保持在55~80,抗滑性能良好;水性环氧树脂的掺入增加了水泥砂浆的粘结性、耐酸腐蚀性和后期抗折强度,但降低了其抗压强度;适量粉煤灰可以增加水泥砂浆的后期抗折和抗压强度。     

Characterization of a nitrogenase CrFe protein from a mutant UW3 of Azotobacter vinelandii grown on a Cr-containing medium

Biological nitrogen fixation is one of the most im-portant biochemical reactions in nature. It is catalyzed by an anaerobic metalloenzyme complex-nitrogenase. Three genetically distinct nitrogenase systems exist in Azotobacter vinelandii (A. vinelandii): Mo-containing nitrogenase, V-containing one and “Fe only” nitro-genase[1―4]. They are composed of two separable com-ponent proteins. For example, conventional Mo-con- taining nitrogenase is composed of component I (MoFe protein) and com…     

骨质疏松患者FGF23与Crosslaps血清浓度检测与分析

目的:探讨骨质疏松症(Osteoporosis,OP)患者外周血成纤维生长因子23(Fibrobalst growth factor-23,FGF23)、Ⅰ互型胶原交联C末端肽(Crosslaps)与25-(OH)D代谢水平与骨质疏松症的关系.方法:选择骨质疏松女性患者32名,年龄48~90岁(OP组),与21名健康人年龄31~50岁(对照组).采用酶联免疫吸附法检测外周血FGF23,Crosslaps及25-(OH)D水平.采用全自动血液生化分析仪检测血钙、血清无机磷、碱性磷酸酶(Alkaline phosphates,ALP)水平,并对OP患者25-(OH)D与FGF23、Crosslaps、血钙、血磷的相关性进行分析.对53名受试者进行骨密度(Bone mineral density,BMD)测量及医学影像学检测.采集OP患者及健康人股骨骨样进行石蜡包埋、切片、HE染色并观察,采用病理学图像分析系统进行形态计量学分析.结果:与对照组比较,OP组患者血清中FGF23、Crosslaps水平显著升高(P0.05);OP患者血清中25-(OH)D水平与FGF23相关系数为-0.012 2,与Crosslaps相关系数为-0.231 7;通过骨组织形态计量学分析,OP患者骨小梁平均厚度、骨小梁面积百分率较对照组显著减少(P0.05),OP组骨小梁间距较对照组显著增大(P0.05).OP患者左侧股骨颈(Femeralneck,FN),Ward's三角(Ward's)骨密度值与对照组均有显著减少(P0.05).通过影像学检测发现OP组X光片透光度有所增加,骨小梁变细,骨皮质变薄.结论:骨质疏松症患者血清中FGF23,Crosslaps因子水平与25-(OH)D水平存在一定相关性.提示其在骨代谢所引起的血清水平变化,以及三者之间的关系可为骨质疏松症的诊断和治疗提供参考.     

黄河三角洲湿地表层土壤磷形态分布特征

2016年10月采集了黄河三角洲典型湿地的表层土壤,并采用SMT(standard measurements testing program)法分别提取了土壤中的TP (total phosphorus)、IP (inorganic phosphorus)、OP(organic phosphorus)、Fe/Al-P (Fe/Al-bound phosphorus)以及Ca-P (Ca-bound phosphorus)．结果表明,土壤中TP的平均质量分数为581.02 mg·kg?1,高于第2次全国土壤普查中土壤TP的平均质量分数．各形态磷质量分数分布从大到小依次为IP、Ca-P、OP、Fe/Al-P,IP约占TP总量的86.98%,是黄河三角洲含量最高的磷形态,而Ca-P则是IP的主要组分,约占IP的85.30%．各形态磷含量在黄河三角洲的分布具有较高的空间异质性,特别是OP和Fe/Al-P,变异系数分别达到了40.20%、39.41%．总的来说,距离黄河比较近的样点土壤中TP和IP含量都较低,有植被分布样点的土壤中OP含量较高．相关性研究表明,TP、IP均与土壤含水量呈现显著的负相关关系,OP与土壤碳质量分数(w(C)/w(P)、w(TOC)、w(TIC))呈现显著的正相关关系,Fe/Al-P和地形因子SOS呈现显著的正相关关系．主成分分析(PCA)也表明IP更容易受到湿地理化性质的影响,而OP和湿地土壤营养水平有很大关系．