新型透明阻燃ABS材料的制备及性能研究

采用MBS型增韧剂(EM500)为基材,加入双酚A双(二苯基)磷酸酯(BDP)和三(三-溴苯基)氰尿酸酯(FR-245)熔融共混制备出溴-磷阻燃剂含量为80%的溴-磷阻燃剂母粒。以此母粒和透明ABS树脂(TE-10S)熔融共混制备出新型透明阻燃ABS材料。通过氧指数(OI)、水平垂直燃烧(UL 94)、锥形量热仪和光度雾度仪测试研究了该透明阻燃ABS材料的阻燃性能和透明性。结果表明:当BDP:FR-245=2:8(质量比),母粒含量为12.5%时,体系的OI达到25%,UL 94达到V-2级;透明性保持率达到84%;母粒含量为25%时,体系的OI达到30%,UL 94达到V-0级,透明性保持率达到50%,同时材料具有优异的力学性能和加工性。     

芳磺酸盐与BDP协同阻燃聚碳酸酯的性能研究

以芳磺酸盐(KTS)与双酚A双(二苯基磷酸酯)(BDP)作为复配体系,制备了阻燃聚碳酸酯(PC)复合材料。通过极限氧指数(LOI)、垂直燃烧、热失重分析(TGA)、力学性能测试实验研究了复配阻燃剂对PC阻燃性能、热稳定性和力学性能的影响。结果表明:当KTS、BDP用量分别为0.1%和12.5%时,体系的LOI达到最大值37.5%,垂直燃烧等级为UL 94V-0级;KTS与BDP复配使用后,对PC有良好的协同阻燃作用,有利于提高材料的热稳定性,同时提高了阻燃PC复合材料的成炭能力,改善了残炭质量。     

无卤阻燃热塑性聚氨酯的制备与性能研究

首先自制了无卤阻燃剂,再与TPU挤出共混,通过热失重分析(TGA)和水平垂直燃烧(UL94)测试对阻燃效果及阻燃机理进行了分析,选择了最佳配方的阻燃剂;随后制备了不同阻燃剂含量的无卤阻燃TPU复合材料,并对复合材料的阻燃性能、力学性能及环保性能等进行了测试。结果表明,自制无卤阻燃剂可以使TPU达到理想的阻燃效果,随着无卤阻燃剂含量的增加,TPU的阻燃性能越来越高,拉伸强度越来越低,当添加量为18%时,复合材料阻燃性可以达到UL94 V-0级(0.8 mm),无滴落,且拉伸强度在20 MPa以上。     

芳香族双磷酸酯复配体系阻燃PPO/HIPS的制备与阻燃性能

采用芳香族双磷酸酯如双酚A双(二苯基)磷酸酯(BDP)和间苯二酚双(二苯基)磷酸酯(RDP),分别与纳米二氧化硅(n-SiO2)、三聚氰胺氰尿酸盐(MCA)复配制备了阻燃PPO/HIPS和阻燃PPO/HIPS纳米材料.利用氧指数(LOI)、水平垂直燃烧(UL94V)、热失重分析(TGA),锥形量热仪(CONE)等技术探讨了复配体系对PPO/HIPS的阻燃作用和阻燃机理.实验结果证明采用复配体系阻燃的PPO/HIPS取得了很好的效果.在相同添加量的情况下RDP比BDP较优.材料氧指数最高达到了35.0%,具UL944 V-O阻燃级.     

无卤阻燃聚苯醚弹性体的研究

以三聚氰胺氰尿酸盐(MCA)为阻燃剂、间苯二酚双(二苯基磷酸酯)(RDP)和二乙基次膦酸铝(ADP)为阻燃协效剂,制备了无卤阻燃聚苯醚(PPO)弹性体材料,并研究了其阻燃性能和力学性能。结果表明,当阻燃剂MCA用量为20%,RDP用量为5%,ADP用量为5%,聚苯醚弹性体UL94(3 mm)垂直燃烧级别达到V-0,氧指数为27.4%,拉伸强度为15.8 MPa。     

不同阻燃剂对聚碳酸酯性能的影响

以六苯氧基环三磷腈、苯氧基环磷腈、双酚A-双(二苯基磷酸酯)(BDP)为阻燃剂，通过熔融共混对聚碳酸酯(PC)进行阻燃改性，得到了3种阻燃PC,采用熔体流动速率仪(MFR)、热重分析仪(TG)、氧指数测定仪和拉力试验机等研究了3种阻燃PC的阻燃性能、热稳定性、流变性能和力学性能。结果表明：当阻燃剂用量为6质量份时，六苯氧基环三磷腈阻燃PC的UL-94阻燃等级达到V-0级，极限氧指数(LOI)达到32.9%,阻燃效果最好。3种阻燃剂的加入均会提升PC的MFR,其中，BDP对PC的MFR提升效果最明显。3种阻燃剂的加入使PC的拉伸强度、断裂伸长率和冲击强度均显著降低，其中，六苯氧基环三磷腈对PC拉伸强度和断裂伸长率的影响最大。     

新型磷-氮系复配阻燃剂在聚丙烯中的应用

采用一种新型磷-氮系阻燃剂与聚磷酸铵(APP)复配成膨胀型阻燃剂,对聚丙烯(PP)进行阻燃改性。研究了阻燃PP的阻燃性能、热分解过程及力学性能。结果表明:当复配阻燃剂添加量为30%时,阻燃改性PP的氧指数和垂直燃烧等级分别达到32.3%和UL94 V-0级,拉伸强度为37.4 MPa,缺口冲击强度为39.5 kJ/m2,并且具有很好的热稳定性。     

聚氨酯/甲基二苯基氧化膦的冷结晶及阻燃性能研究

将新型阻燃剂甲基二苯基氧化膦（DPMP）与聚氨酯（PU）复合,并采用片状黏土为协效剂,通过极限氧指数（LOI）测试、垂直燃烧测试（UL 94）和微型量热分析（MCC）研究了DPMP和黏土对复合材料阻燃性能的影响,并采用示差扫描量热仪（DSC）、热失重分析仪（TG）分析了复合材料的结晶性能及热降解行为。结果表明,DPMP能促进PU冷结晶,从而提高其模量和力学性能。当PU复合材料中DPMP含量（质量分数,下同）为10%时,PU的LOI值从23%增加到28.3%。PU/10%DPMP的模量、断裂伸长率和拉伸强度分别为1.37 MPa、1 042%和13.84 MPa,纯PU的相应分别为1.17 MPa、811%和11.32 MPa。当体系进一步加入黏土,1%的黏土即可使PU/DPMP的滴落现象消失,UL 94达到V-0级。     

膨胀型无卤阻燃PP/EVA电缆料的研制

介绍了膨胀型无卤阻燃PP/EVA电缆料的制备方法,采用氧指数仪、UL94垂直燃烧箱、电子万能试验机及TG热重分析仪等对其进行了表征。结果表明:经阻燃后氧指数已提高到34.5%;燃烧等级已达到UL94V0级;拉伸强度为15.11MPa,断裂伸长率为557.67%;600℃时,残炭量达到17.49%。     

碳微球/勃姆石/PP复合材料的制备及性能分析

以碳微球(CMS)和勃姆石(BM)为阻燃剂，打包盒PP废塑料(H-PP)为原材料，通过熔融挤出制备CMS/BM/H-PP复合材料，利用极限氧指数(LOI)、UL 94、锥形量热仪和热失重分析(TG)等对复合材料的阻燃性、热分解温度、力学性能和热变形温度(HDT)进行分析。结果表明，BM可以有效阻燃H-PP。在H-PP中加入30%的BM,30-BM/H-PP的LOI达到27.8%,阻燃等级为UL 94 V-1级，T_5%、HDT、拉伸和弯曲强度分别为321.2℃、95.8℃、19.4 MPa和22.8 MPa,与H-PP相比，其强度降低，热分解温度和HDT升高；以BM为主阻燃剂，适量的CMS和BM在H-PP中具有协同阻燃效果；在H-PP中加入4%的CMS和26%的BM,4-CMS/26-BM/H-PP的LOI为29.8%,阻燃等级为UL 94 V-0级，其T_5%、拉伸强度、弯曲强度、TTI和FPI分别为332.4℃、22.5 MPa、26.2 MPa、37 s和0.15(m²·s)/kW,与30-BM/H-PP相比，有显著提...     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.