硅烷交联管材专用HDPE 2300XM的性能与应用

在高密度聚乙烯(HDPE)装置上工业化开发了硅烷交联聚乙烯(PEXb)管材专用HDPE 2300XM。性能测试与应用研究表明:2300XM具有合理的熔体流动速率与密度,其物理性能、流变性能及PEXb管材性能与进口专用树脂HDPE XL6500相当,满足PEXb管材快速挤出与长期使用要求。由2300XM生产的PEXb管材通过了110℃,8 760 h静液压状态下热稳定性试验;2300XM是国内首个通过10 000 h长期静液压分级试验的冷热水用交联聚乙烯管材基础树脂,其PEXb管材最小要求强度等于10 MPa,表明2300XM为交联PE100级管材基础树脂。     

PE100级管材专用树脂的结构与性能

通过熔体流动速率、差示扫描量热法分析、力学性能以及管材静液压试验等研究了3种PE100级管材专用树脂的结构与性能。结果表明:3种树脂在200℃条件下的氧化诱导时间均大于120 min,耐热氧老化性能良好;GC100S的熔流比为26.3,结晶度为60.1%,冲击强度为58.49 kJ/m~2,在80℃,5.4 MPa条件下的短期静液压测试耐压时间为348 h,均较其他两个试样好,为管材专用树脂的质量提升提供了技术支持。     

给水PVC-U管材环应力与环境温度的关系

考察了试验环境温度对给水PVC-U管材(Φ110×2.7和Φ90×2.8)静液压环应力和爆破环应力的影响。结果表明:①环境温度对两种规格管材环应力的影响一致,基本呈线性关系;②环境温度每增加1℃,静液压环应力减少0.63MPa,爆破环应力减少0.54MPa。     

挤出工艺条件对PP-R管材性能的影响

采用单螺杆挤出无规共聚聚丙烯(PP-R)管材,探讨挤出加工温度、螺杆转速、冷却水温度等工艺条件对PP-R管材性能的影响。结果表明:当加工温度在200℃左右,螺杆转速为96.5 r/min,冷却水温在20～25℃时,制备的dn20×en2.8规格的PP-R管材加工性能最稳定,力学性能及静液压性能优异。为进一步确定管材性能的影响因素,采用正交试验法对挤出工艺条件进行优化,正交试验结果表明:加工温度为200℃,螺杆转速为96.5 r/min,冷却水温30℃。     

双轴取向聚氯乙烯管材最佳拉伸温度和径向拉伸比的研究

以聚氯乙烯（PVC）树脂为主要原料，通过一步法挤出加工方式，采用纯净配方，在配方和轴向拉伸比不变的情况下，将拉伸温度设置为80、85、88、90 ℃，径向拉伸比设为1.8（坯料管外径63 mm、壁厚5.2 mm）和1.9（坯料管外径为60 mm、壁厚6.0 mm）制备双轴取向聚氯乙烯（PVC⁃O）管材。通过对不同工艺生产的管材进行静液压试验、落锤冲击试验、拉伸试验、环刚度试验来表征管材的力学性能。结果表明，适合此配方和轴向拉伸比的PVC⁃O管挤出成型的最佳拉伸温度为85 ℃，最佳径向拉伸比为1.9。     

可稀释使用钢丝管粘接树脂的性能及其应用研究

自制EN312是一种高性能的、可稀释使用的钢丝复合管用粘接树脂。测试了其主要性能,并研究了其添加不同比例管道级聚乙烯2480稀释应用的管材的性能。结果表明:EN312添加60%~80%的2480使用,对钢丝的剪切强度影响不大;EN312添加60%~80%的2480作为粘接树脂应用于dn160×2.5MPa钢丝管,管材的剥离强度、爆破压力、20℃、2PN、1h静液压、60℃、1.2PN、165h静液压均达到标准要求;EN312稀释使用表现出良好的抗高低温冲击穿丝及扣压穿丝能力。     

PE 100级管材专用树脂的开发

介绍了PE100级管材专用树脂的开发历程及等级认证结果;研究了管材专用树脂的常规性能、加工性能及短期静液压强度。结果表明：开发的2种管材专用树脂的应力置信下限值分别为10．261MPa和10．446MPa．达到PE100级,两者的加工性能均好。DGDB 2480 HBK的耐慢速裂纹增长性能超过500h．短期静液压强度达到GB 15558．1～2003要求,可用于PE100级燃气管的生产。     

给水用聚丙烯管材料的研究

通过剖析进口PPR（无规共聚聚丙烯）管材料的性能选择了一种国产的市售PPR树脂为基料，经耐热水萃取及烘箱热老化试验确定了较佳的稳定剂配方，对专用料及其挤出的管材性能分析测试结果表明，专用料性能与进口料相当。     

无规共聚PP热水管专用树脂的开发

采用无规共聚聚丙烯（PP—R）EPlD30P为基础树脂,添加复合助剂,生产出PP—R热水管专用树脂EP2D30P。对其分子结构、性能的分析及管材挤出试验表明,该专用树脂的物性指标全部达到设计要求,缺口冲击强度大于等于55．54kJ／m^2,氧化诱导期大于等于113．5min,且加工性能优良,管材外观满足使用要求．并通过了1000h静液压试验。     

X射线荧光光谱法在聚丙烯给水管检测中的应用

无规共聚聚丙烯(PPR)管是一种新型的塑料冷热水供水管,其优越性能已越来越得到社会的认可。采用X射线荧光光谱法(XRF)对PPR全新粒料和再生料以及以此制备的管材分别进行元素测定,并对自制的管材进行静液压测试(95℃,1 000 h)。试验结果表明:纯PPR粒料与再生料元素含量差异较大,制备成管材后含量差值减小;Fe,Cu,As,Pb等元素含量在PPR再生粒料和含再生料的管材中远超出检出限,而在纯粒料和纯PPR管材中未检出。静液压测试显示3批含再生料的管材样品在试验后均出现破裂渗漏,不可作为冷热水管使用,这与X射线荧光光谱法结果一致。因此,可以通过元素含量的变化以及Fe,Cu,As,Pb等元素含量是否超出检出限来判断PPR管材中是否掺杂有再生料。     

Joint effects of rotational extrusion and TiO2 on performance and antimicrobial properties of extruded polypropylene copolymer pipes

In this study, effects of titanium dioxide (TiO₂) and rotation extrusion on structures and properties of polypropylene random copolymer (PPR) pipes were investigated. The experimental results showed that with the presence of TiO₂, not only the antibacterial ability of PPR pipe was improved significantly but also the toughness was enhanced since a large number of PP chains were promoted to crystallize into β‐form crystals. Furthermore, when rotation extrusion was introduced into the process of PPR pipe, the drag hoop flow caused by mandrel and die rotation was superposed on the axial flow, so the polymer melts in the annulus underwent a helical flow and its flow direction deviated from the axis to drive the molecular orientation off the axial direction, bringing out the increased hoop strength. As a result, PPR pipe with excellent performance was prepared under the combined effect of rotation extrusion and TiO₂. The antibacterial activity was 99.2%, the hoop tensile strength reached 27.5 MPa, 67.7% higher than that of the convention‐extruded PPR pipe with TiO₂, and the impact strength was 10.9 kJ/m², increased by 81.6% compared to that of the rotation‐extruded pure PPR pipe. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42410.     

搭接焊铝塑管与对接焊铝塑管的长期静液压强度计算

将16-32规格的搭接焊铝塑管的长期静液压试验曲线外推至50年,通过考虑1个与对接焊铝塑管相同的总体设计系数（C=1.25）,证明在T0=95 ℃的长期工作温度下,16-32规格的搭接焊铝塑管与对接焊铝塑管的允许工作压力P0相当。搭接焊铝塑管也能满足95 ℃、1.25 MPa下使用寿命为50年的要求。根据国家标准对搭接焊铝塑管与对接焊铝塑管的铝管层最小壁厚和最小拉伸强度的要求,计算出16-50规格的搭接焊铝塑管与对接焊铝塑管的P0。结果表明,小规格二者的P0相当,大规格对接焊铝塑管的P0优势明显。     

The effect of storage of poly(propylene) pipes under hydrostatic pressure and elevated temperatures on the morphology, molecular mobility and failure behaviour

One of the important applications of random poly(ethylene propylene) copolymer (PPR) is the production of hot water pipes. The pipes can be used under hydrostatic pressure as well as at elevated temperatures up to 70 °C continuously for 50 years and at short time at 80 °C. If a pipe is used at higher temperatures for longer times it could fail earlier. Knowledge of usage time and temperature is vital for determining the origin of a failure of PPR pipes. Several techniques are used for determining changes in chemical and physical structures upon long-time annealing of PPR pipes at different temperatures. Techniques, which are sensitive to thermo-oxidative degradation of PPR and consumption of stabilizers, are not very sensitive for determining storage time longer than one year. The molar mass of PPR does not change upon long-time annealing. It is shown that crystallinity of the samples, as determined by wide angle X-ray diffraction (WAXD), is not largely affected by storage time at elevated temperatures. It is also shown that onset of melting, as measured by differential scanning calorimetry (DSC), increases with increasing storage temperature, which is apparently caused by the perfection of crystalline structure at higher temperatures. Onset of melting allows determining the maximum storage temperature of PPR pipes. It is shown that proton solid-state NMR transverse magnetization (T₂) relaxation analysis is the most sensitive tool for determining changes in PPR samples that are caused by storage time of PPR pipes under hydrostatic pressure. The method provides information on molecular mobility and phase composition of PPR samples. Four different phases are analysed with this method: (1) crystalline phase and rigid fraction of the amorphous phase, (2) semi-rigid crystal-amorphous interface, (3) soft fraction of the amorphous phase and (4) rubbery-like material. The most pronounced changes upon long storage time are observed for the rigid fraction of PPR (fraction 1). This suggests that long time annealing of the samples at temperatures far above T_g (about 0 °C) results in (1) perfection of existing crystals and the formation of new crystals, which act as physical junctions leading to immobilization of the amorphous phase, (2) chain elongation in the amorphous phase due to creep under hydrostatic pressure, and (3) an increase in the gradient of concentration of ethylene-rich chain fragments through the mobile fractions of the amorphous phase. All these changes cause embrittlement of the samples. Thus, the combination of DSC and solid-state NMR measurements is a powerful tool for determining the critical time and temperature conditions causing breakage of PPR pipes and fittings.     

等规聚丁烯-1管材料的耐热老化性能研究

等规聚丁烯-1(iPB-1)是一种优异的管道材料,特别适合制备薄壁小口径受压管材,iPB-1树脂近年已逐步国产化,但耐长期静液压定级实验评估长期使用寿命时仍有不足。经考察并对比Basell公司进口和国产两种iPB-1管材料在模拟长期静液压实验的95℃热水和空气气氛常压热烘条件下氧化诱导时间和拉伸性能的变化规律,发现国产iPB-1管材料短期耐水抽提性优于进口料但空气气氛下的耐热老化性略显偏弱,国产料改性后在95℃热水中4 000 h后的拉伸强度和断裂伸长优于进口料而杨氏模量偏低,有更突出的强度和韧性优势。     

Synergistic effect of self‐assembling nucleating agent and crystallization promoter on polypropylene random copolymer pipes via rotation extrusion

In this study, high hoop tensile strength and toughness polypropylene random copolymer (PPR) pipes were successfully prepared through rotation extrusion and synergistic effect of self‐assembling nucleating agent (TMB‐5) and crystallization promoter (isotactic polypropylene, iPP). The result indicated low temperature toughness of PPR pipes could be improved by incorporating TMB‐5 and iPP, as the result of highly improved PPR crystallization capability and abundant β‐form crystal production. Both molecular chains and anisotropic crystallites deviated off the axial direction due to the hoop stress generated by rotation extrusion, leading to increased hoop orientation and pronouncing enhancement in hoop strength. Accordingly, the hoop tensile strength and impact strength of the modified PPR pipe reached 28.9MPa and 5.7kJ/m², increased by 126% and 43% compared to the convention‐extruded PPR pipe. POLYM. ENG. SCI., 56:866–873, 2016. © 2016 Society of Plastics Engineers     

Synergistic effects of α/β‐nucleating agents on propylene‐ethylene random copolymer: New clues for the pipe extrusion

Adding β‐nucleating agents (β‐NAs) has been generally considered as an effective approach to induce the formation of β‐crystals in propylene‐ethylene random copolymer (PPR). However, it is still difficult to obtain the expected percentage of β‐crystal under normal processing conditions, due to the temperature control is always a key factor no matter with or without adding β‐NAs. We assumed that simultaneously adding both α‐ and β‐NAs to PPR in rational ratios would facilitate the growth of β‐crystal. The effects of adding various amount of α‐ and/or β‐NAs on the α‐ and β‐crystallization behavior and morphology were investigated. More importantly, the influence of temperature control on inducing β‐crystal in the presence of different NAs was parallel explored by utilizing sample bars prepared via injection molding and sample pipes produced from a typical industrial extrusion line. Different crystallization situations were carefully discussed in response to various nonisothermal crystallization processes in laboratory experiments and in actual pipes extrusion. At last, the mechanical properties of PPR samples were examined to provide new clues for further study of PPR pipes. POLYM. ENG. SCI., 56:1089–1095, 2016. © 2016 Society of Plastics Engineers     

PPR铜塑管件的开发

采用注塑法生产出无规共聚聚丙烯(PPR)铜塑管件。讨论了铜件表面处理、铜件沟槽深度、注射压力、注射保压时间等工艺条件对PPR铜塑管件质量的影响。结果表明,当铜件表面经镀铬处理、铜件沟槽深度2.0mm、注射压力60MPa、塑化温度200℃、注射保压时间20s时,Dn63规格的PPR铜塑管件质量较理想。     

聚乙烯给水管耐候性的研究

将含有以及不含有光稳定剂的两种兰色聚乙烯给水管,在标准暴露场同时进行自然气候曝露,对不同曝露时间的管材取样和进行力学性能、热稳定性,静液压强度和色差的测定。根据试验结果分析了自然气候对聚乙烯管材的老化作用,断裂伸长率、静压强度变化和保留率是评价聚乙烯管材耐候性比较合适和灵敏的指标。指出应采取有效的光稳定化和热氧稳定化方法处理聚乙烯给水管树脂。     

Effect of rotation extrusion and molecular weight on ductile failure of polyethylene pipes under hydrostatic pressure

ABSTRACT

In this study, two kinds of polyethylene (PE) with different molecular weight were processed into the pipes via rotation extrusion and the failure behaviours under hydrostatic pressure as well as molecular relaxation were investigated. The experimental results showed that the high molecular weight PE exhibited slower relaxation behaviour with higher relaxation activation energy to facilitate the formation of shish-kebab under flow field, while for the low molecular weight one, the stretching molecules easily relaxed back coil state and spherulites were prone to form. Therefore, the low molecular weight PE pipes via convention and rotation extrusions had similar isotropic spherulite morphology and short failure times. In the case of high molecular weight PE, during the convention extrusion, polymer melts flowed along the axial direction to induce the alignment of shish-kebab accordingly, which went against to the hoop stress in hydrostatic pressure. With the rotation of mandrel and die, the direction deviated from the axis so that PE pipe exhibited better resistance to the hoop stress. The failure time was 182?h, 264% longer than the convention-extruded one. Accordingly, a new strategy to prepare high hydrostatic pressure PE pipe under cooperative effects of rotation extrusion and long molecular relaxation time was proposed.     

含苯炔基侧链的聚酰亚胺树脂及其复合材料

采用联苯酐(3,4′-BPDA)与4,4′-二氨基二苯醚(4,4-ODA),3,5-二氨基-4′-苯炔基二苯甲酮(DPEB),苯炔基苯酐(PEPA)制备了不同分子质量的聚酰亚胺树脂。通过流变分析,热重分析,红外光谱,动态热力学分析及静态力学性能测试等研究了分子结构,分子质量等因素对聚酰亚胺树脂耐热性和力学性能的影响。结果表明,合成的聚酰亚胺树脂具有优异耐热性能和较高的韧性,固化后树脂的玻璃化转变温度为379℃,5%热失重温度高于550℃,并且浇注体的拉伸强度是61 MPa,断裂伸长率是6.2%.碳纤维复合材料的室温弯曲强度为1 850 MPa,层间剪切强度为84 MPa,316℃时弯曲强度为946 MPa,剪切强度为46 MPa,具有良好的高温力学保持率。