含磷/氮/硫环交联磷腈微纳米管的合成及对环氧树脂的阻燃作用

采用原位模板法,以六氯环三磷腈(HCCP)和二羟基二苯砜(BPS)为原料合成了一种环状交联型不溶不熔的磷腈大分子——聚环三磷腈-二羟基二苯砜(PZS)微纳米管,研究了PZS对环氧树脂(EP)的阻燃作用及阻燃机理.利用红外光谱(FTIR)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)对PZS微纳米管进行了表征;采用热重分析(TG)考察了EP/PZS阻燃材料的热稳定性,并通过极限氧指数(LOI)和微型量热分析(MCC)测试了EP/PZS的阻燃性能.热降解实验结果表明,PZS微纳米管的加入使环氧树脂热降解温度降低,但残炭率显著提高.PZS微纳米管可以显著提高环氧树脂的阻燃性能,当阻燃剂添加量为5%时,环氧树脂的残炭率提高了46%,热释放速率峰值降低了约40%;LOI值从纯环氧树脂的26.0%提高到了30.6%.PZS微纳米管的加入还增强了环氧树脂的力学强度.阻燃性能的显著提高和力学性能的改善归因于PZS微纳米管在环氧树脂基体中的良好分散,以及燃烧炭化过程中生成的石墨化程度较高的类石墨烯结构的残炭,具有较高的抗氧化能力.研究结果表明,PZS微纳米管是一种优良、高效的具有潜在应用价值的阻燃剂.     

New cyclic phosphonium salts derived from the reaction of phosphine-aldehydes with acid

Various cyclic phosphonium structures are formed in high yield by the deprotection of unstable phosphine-aldehydes in acidic solution. When there is a methylene spacer between the phosphine and the aldehyde, a phosphonium ion [PHR₂CH₂CH(OEt)₂]Br₂, R=iPrOH, Et is obtained. Reaction of these phosphonium salts with water produces the dimers [-PR₂CH₂CH(OH)-]₂[Br]₂ R = iPr, Et. When there is an ethylene spacer as in PPh₂CH₂CH₂CH(OCH₂CH₂O), a remarkable tetramer with a 16-membered ring [-PPh₂CH₂CH₂CH (OH)-]₄[Cl]₄ forms as one diastereomer in hydrochloric acid solution. Reaction of HCl with the protected phosphine-aldehyde with a propylene spacer (PPh₂CH₂CH₂CH₂CH(OCH₂CH₂O)) results in the formation of the monomeric phosphonium salt [-PPh₂ CH₂CH₂CH₂CH(OH)-]Cl with a 5-membered ring. Solid state structures of different ring types were determined using X-ray diffraction experiment.     

电感耦合等离子体-质谱测定石灰性土壤中的有效磷

采用电感耦合等离子体一质谱法测定石灰性土壤中的有效磷,方法检出限为0.090μg/g.通过对国家土壤有效态一级标准物质和行业标准物质测试,测定结果与标准值基本一致;对GBW 7413、GBw 7414、ASA-8、ASA-9标准物质进行11次测定的相对标准偏差(RSD)均小于5%.     

Phosphorus gettering of precipitated Cu in single crystalline silicon based on rapid thermal process

In this paper, we have investigated the effect of phosphorus diffusion gettering on the precipitated Cu in silicon via rapid thermal process (RTP). It is found that, for dot-like or star-like precipitates, the RTP-based phosphorus diffusion technique is efficient for gettering out the precipitated Cu. A two-step RTP gettering process is much more effective than a single-step RTP process. Furthermore, the choice of oxygen ambient can enhance the Cu gettering efficiency due to the involvement of considerable self-interstitial silicon atoms. The minority carrier lifetime of the sample subjected to RTP-based phosphorus gettering has also been verified to be significantly enhanced. These results are of interest for the gettering engineering of high-efficiency silicon solar cells.     

工业硅中钛、磷的测定

在pH1的盐酸介质中，Ti（Ⅳ）与变色酸形成桔红色配合物，Fe（Ⅲ）干扰用坏血酸还原消除；在0.42mol/L硫酸介质中，PO4^3-与钼酸铵形成磷钼杂多酸，用抗坏血酸还原为钼蓝，为此对工业硅中钛、磷进行光度法测定，结果令人满意。     

Decomposition procedure with aqua regia and hydrofluoric acid at room temperature for the spectrophotometric determination of phosphorus in rocks and minerals

A rapid spectrophotometric method for the determination of phosphorus in rocks and minerals is described. The sample solution is prepared by treatment with hydrofluoric and aqua regia at room temperature. Unreacted fluoride ions are complexed with boric acid. As fluoride ions do not have to be removed by heating, the method is rapid and avoids the use of platinum ware.     

V/P复合氧化物上C-H键活化的密度泛函研究

选择氧化催化剂通常为多组分复合氧化物.一般认为,高价过渡金属的端末双键氧(M=O)是烷烃活化的中心,而非金属端氧(NM=O)与烷烃活化无关.但近期的理论研究发现,复合氧化物中非金属端氧也可能参与烷烃活化.本文采用密度泛函方法(B3LYP)对比V=O和P=O的脱氢活性,并深入揭示二者的差异. H脱除反应可以视为是质子偶联电子传递的过程.对于V/P复合氧化物, V5+充当电子的受体,而V=O和P=O均可接受质子.由于P=O具有更强的质子化能力,导致PO–H键能比VO–H有利6–10 kcal/mol.对于烷烃活化, V=O和P=O脱氢的能垒均可与反应焓变很好地关联,但二者线性回归的截距相差6.2 kcal/mol,说明在相同的焓驱动下, P=O脱氢需要克服更高的能垒.根据Marcus模型,反应的能垒不仅取决去反应焓变,还与内部重组能有关.计算表明,在脱氢过程中, P=O需克服的重组能为128–140 kcal/mol,比V=O过程高出21–23 kcal/mol.这很好地解释了前面的计算结果.应该指出的是,除了反应热力学驱动和重组能外,在势能曲线相交处的电子耦合作用(?HAB?)亦对能量有一定的影响.丁烷选择氧化制顺酐可能经过2-丁烯,丁二烯,2,5-二氢呋喃和丁烯酸内酯等一系列中间体,共有8个H原子在反应过程中需要脱除.对于丁烷的脱氢, P=O的能垒仅比V=O低1.3 kcal/mol,说明初始反应时二者是竞争的.但对于2-丁烯和2,5-二氢呋喃,二者活化能的差距增加为6–7 kcal/mol,说明这时P=O脱氢将占主导.而对丁烯酸内酯活化,二者活化能的差异又缩小到2.5 kcal/mol,表明V=O又具有一定的竞争力.事实上,这种能垒的差异与端氧的亲核性密切相关.P=O更具亲核性,因此有利于被更具酸性的C–H键进攻.根据Evens的估计,烷烃C–H键的pKa为50左右,而烯丙基性C–H为43.这就很好地解释了为什么2-丁烯和2,5-二氢呋喃更容易和P=O发生反应,而丁烷脱氢二者差异不大的原因.这些理论研究可以加深我们对复合氧化物催化剂上活性位点的认识,并为催化剂的理性设计提供理论支撑.     

Synthesis,NMR‐Spectroscopy,and Molecular Structure of a Phosphonyl Ene Diamine

First examples of ene diamines with a phosphonate function at the C=C double bond were obtained by the reaction of dialkyl H‐phosphonates with bis(N‐tert‐butyl)‐diimine derived from glyoxal, [1,4‐bis(tert‐butyl)‐1,4‐diaza‐1,3‐butadiene], and isolated as hydrochlorides. Preferentially the cis‐diamine is formed. The new phosphonates are characterized by multinuclear NMR spectroscopy(¹H, ¹³C, ³¹P). In addition the methyl ester 8a was characterized by ^14,15N NMR spectroscopy as well as by several 2D NMR techniques and single‐crystal X‐ray diffraction, unequivocally establishing the ene diamine structure. In the crystal dimers of the cations are formed by P–O ··· H–N hydrogen bonding.     

Inherent flame retardation of bio-based poly(lactic acid) by incorporating phosphorus linked pendent group into the backbone

The molecular design for inherently flame-retardant poly(lactic acid) (IFR-PLA) was outlined and achieved by chemically incorporating an effective organophophorus-type flame retardant (FR) into the PLA backbone via the chain extension of the dihydroxyl-terminated prepolymer with 1, 6-hexamethylene diisocyanate (HDI). The structure of IFR-PLA was characterized by ¹H- and ³¹P-nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. IFR-PLA was further blended with the commercial PLA to prepare flame retardant PLA blends (PLA-FR blend). The relevant properties of IFR-PLA and PLA-FR blends were evaluated by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), limiting oxygen index (LOI) measurements and UL-94 tests. The thermal analysis revealed that the char yield of IFR-PLA and PLA-FR blend above 400 °C was greatly enhanced compared to that of pure PLA. The LOI value was significantly improved from 19 for pure PLA to 29 when 1 wt% of phosphorus content was introduced and all IFR-PLA samples achieved V-0 rating in the UL-94 tests. PLA-FR blends had an LOI value of 25-26 and UL-94 V-2 rating at 20 wt% of IFR-PLA content. The tensile strength of all the FR PLA systems was ca. 60 MPa. The method used in this study provided a novel route to permanently flame retard PLA.