纳米SiO<sub>2</sub>与间苯二酚-双(二苯基磷酸酯)对聚碳酸酯-ABS合金的协同阻燃机制

高顺; 郭正虹

doi:10.13801/j.cnki.fhclxb.20200311.002

纳米SiO₂与间苯二酚-双(二苯基磷酸酯)对聚碳酸酯-ABS合金的协同阻燃机制

高顺,
郭正虹^,

浙大宁波理工学院　高分子材料与共混实验室，宁波 315100

基金项目: 国家自然科学基金(51991355)

详细信息

通讯作者:
郭正虹，博士，副教授，研究方向为阻燃高分子复合材料　E-maill：guozhenghong@nit.zju.edu.cn

中图分类号: TB324
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出版历程
- 收稿日期: 2019-12-27
- 录用日期: 2020-02-01
- 网络出版日期: 2020-03-11
- 刊出日期: 2020-11-14

Synergistic flame retardant mechanism of nano SiO₂ and resorcinol bis(diphenylphosphate) on polycarbonate-ABS blends

GAO Shun,
GUO Zhenghong^,

Lab of Polymer Material and Engineering, NingboTech, Zhejiang University, Ningbo 315100, China

摘要

摘要: 选用以凝聚相阻燃机制为主的间苯二酚-双(二苯基磷酸酯)(RDP)作为阻燃剂，纳米SiO₂为协效剂，以熔融共混法制备了聚碳酸酯(PC)-丙烯腈-丁二烯-苯乙烯共聚物(ABS)阻燃合金。通过垂直燃烧(UL94)和锥形量热测试(Cone)探究了纳米SiO₂与RDP复配对PC-ABS合金阻燃性能和燃烧行为的影响。采用SEM观察燃烧残炭的微观形貌，用EDS分析炭层表面元素含量的变化，进一步探究了纳米SiO₂与RDP在PC-ABS凝聚相中的协效阻燃机制。通过拉伸性能和冲击性能测试研究纳米SiO₂与RDP复配对PC-ABS合金力学性能的影响及甲基丙烯酸甲酯-丁二烯-苯乙烯(MBS)对PC-ABS合金的增韧增容作用。结果表明，纳米SiO₂与RDP可以在凝聚相中形成Si—O—P化合物，对PC-ABS合金的燃烧炭层起到增强作用，从而改善PC-ABS合金的阻燃性能；适量MBS的加入可以提高PC-ABS合金的冲击强度和断裂伸长率，但会降低其阻燃性能。
- 聚碳酸酯(PC) /
- 丙烯腈-丁二烯-苯乙烯共聚物(ABS) /
- 纳米SiO₂ /
- 阻燃 /
- 凝聚相 /
- 力学性能
Abstract: The flame retardant polycarbonate (PC)-acrylonitrile-butadiene-styrene (ABS) blends was prepared by melt blending with resorcinol bis(diphenylphosphate) (RDP) (mainly based on condensed phase flame retardant mechanism) and nano SiO₂ as the synergist. The effects of nano SiO₂ and RDP on the flame retardancy and combustion behavior of PC-ABS blends were investigated by vertical combustion (UL94) and cone calorimetry (Cone). SEM was used to observe the micro morphology of burning carbon residue, and EDS was used to analyze the change of element content on the surface of carbon layer, so as to further explore the synergistic flame retardant mechanism of nano SiO₂ and RDP in the condensed phase of PC-ABS. The effects of nano SiO₂ and RDP on the mechanical properties of PC-ABS blends and the toughening and compatibilizing effects of methyl methacrylate-butadiene-styrene (MBS) on the blends were studied by tensile and impact tests. The results show that nano SiO₂ and RDP can form Si—O—P compound in the condensed phase, which can enhance the combustion carbon layer, thus improving the flame retardancy of PC-ABS blends; The impact strength and elongation at break of the PC-ABS blends can be increased with the addition of MBS, but the flame retardancy can be decreased.
- polycarbonate (PC) /
- acrylonitrile-butadiene-styrene (ABS) /
- nano SiO₂ /
- flame retardant /
- condensed phase /
- mechanical property

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复合管多用于海洋油气输送，其中非粘接的钢带缠绕增强复合管多用于浅海油气运输^[1-3]。钢带缠绕增强复合管不仅克服了一般热塑性复合管质量密度低的缺点，且具有顺应性高、生产安装费用低及可再回收利用等特点^[4]。但长期恶劣的服役环境极易造成管道失效，进而引发油气泄露事故^[5]，因此开展海底复合管力学行为研究对钢带缠绕增强复合管结构设计、安全评价、操作维修等具有重要意义。

许多学者对钢带缠绕增强复合管进行了探索研究，如Bai等^[6-7]利用压溃试验和数值模拟研究发现，初始椭圆度、径厚比越大，钢带缠绕增强复合管极限抗外压能力越低。Bai等^[8]、Jiang等^[9]和Bai等^[10]利用轴向拉伸试验和数值模拟对钢带缠绕增强复合管进行研究发现，在纯拉伸载荷作用下，钢带缠绕增强复合管的拉伸刚度随着伸长量的增大而减小；同时建立了相应的解析模型并进行求解。Liu等^[11]基于蒙特卡洛(Monte-Carlo)及一次二阶矩(FOSM)相组合的方法矫正了钢带缠绕增强复合管的设计安全系数。学者们对复杂载荷下其他类型复合管进行了研究，如姜豪等^[12]建立了深海非粘结柔性管力学模型，分析了其在组合载荷工况下的力学性能。Gong等^[13]、Sertã等^[14]和Fe´ret等^[15]预测了深海柔性管的铠装层在轴向压缩、弯曲及外压下的屈曲失效。Bathtui^[16]给出用于模拟非粘结柔性立管在轴向拉伸、弯矩、内外压作用下结构响应的简化本构模型。Ramos等^[17]建立了深海柔性管在弯曲、扭转等组合载荷条件下的全滑动力学模型并得到相应解。Ramos等^[18]考虑管道层间间隙，提出了组合载荷下深海柔性管力学响应的计算模型，并进行了相应试验。Merino等^[19]采用试验和有限元方法研究发现，深海柔性管在内外压及拉伸条件下为线性响应，扭转载荷下为非线性响应。Gong等^[20]研究了深水夹芯管屈曲传播特性，提出了非粘接下深水夹芯管系统的传播压力经验表达式。Xue等^[21-23]对海底腐蚀管道在外部静水压力作用下的稳态屈曲拓展现象进行了非线性有限元分析。同时，提出一种夹芯管屈曲传播的三维分析方法，从壳的塑性稳定性理论角度描述了一种屈曲传播现象的综合机制，并提出了夹芯管的一阶剪切变形理论，推导了非浅水区夹芯层圆柱壳的平衡微分方程。

综上所述，目前针对钢带缠绕增强复合管的力学响应研究大多限于单一载荷下的试验或数值模拟，而对复杂载荷条件下的力学响应问题研究较少。由于海洋环境复杂多变，海底管道服役环境恶劣，钢带缠绕增强复合管承受复杂载荷，包括轴向拉力、弯曲载荷及内外压等，会加速管道失效。因此，本文开展多种复杂载荷下钢带缠绕增强复合管的力学特性研究。

1. 数值计算模型及验证

钢带缠绕增强复合管包含防漏和耐腐蚀的内层聚乙烯(PE)管、抵抗内外压的两层螺旋方向相反的钢质增强带、减小摩擦的保护层及抵抗外腐蚀的外层聚乙烯(PE)管^[24]，如图1所示。以长度为1 100 mm的钢带缠绕增强复合管为研究对象，建立如图1所示的数值计算模型。其中：1为内层PE管；2为内层缠绕钢带；3为外层缠绕钢带；4为保护层；5为外层PE管。

图 1 钢带缠绕增强复合管结构及数值计算模型

Figure 1. Structure and numerical calculation model of reinforced composite pipe wound with steel strip

PE—Polyethylene

下载: 全尺寸图片幻灯片

由于钢带缠绕增强复合管各层之间存在非线性接触，因此对较厚的内、外PE管采用C3D8R实体单元，对较薄的钢带及保护层采用S4R壳单元。接触关系采用法向硬接触和切向罚接触^[24]，钢带之间的摩擦系数为0.18，钢带与PE管之间的摩擦系数为0.22。管道一端完全固定，另一端施加轴向拉伸位移。根据文献[8]的试件，设置如表1所示的几何参数及材料属性。

表 1 钢带缠绕增强复合管的几何模型及材料参数

Table 1. Geometric and material parameters of reinforced composite pipe wound with steel strip

Model	Inner ring radius/mm	Thickness/mm	Helix angle/(°)	Width/mm	E/GPa	μ	Yield strength/MPa
Inner PE pipe	25.0	6.0	—	—	1.04	0.40	20
Inner steel strip	31.0	0.5	54.7	52	199.00	0.26	850
Outer steel strip	31.5	0.5	−54.7	52	199.00	0.26	850
Protective layer	32.0	1.0	—	—	1.04	0.40	20
Outer PE pipe	33.0	4.0	—	—	1.04	0.40	20
Notes: E—Elastic modulus; μ—Poisson’s ratio.

下载: 导出CSV

| 显示表格

文献[24]提出了计算钢带缠绕增强复合管轴向拉伸刚度的简化解析模型，可知钢带轴向拉力为

$\left\{ \begin{array}{l} {F_{{\rm{steel}},i}} = nbtE\cos \theta \cdot \left( {\dfrac{{\Delta L}}{L}{{\cos }^2}\theta + \dfrac{{{u_{{\rm{R}}i}}}}{{{R_{{\rm{m}}i}}}}{{\sin }^2}\theta } \right){\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} {\kern 1pt} \left\{ {i = {\rm{1,}}2} \right\}\\ {u_{{\rm{R}}i}} = - \dfrac{{{{\rm{\Lambda }}_1}{\Lambda _5} + {\Lambda _6}}}{{1 + {\Lambda _2}{\Lambda _5}}}\\ {\Lambda _1} = \beta E{\sin ^2}\theta \cdot t\dfrac{{\Delta L{{\cos }^2}\theta }}{L}\left( {\dfrac{1}{{{R_{{\rm{m}}1}}}} + \dfrac{1}{{{R_{{\rm{m}}2}}}}} \right)\\ {\Lambda _2} = \beta E{\sin ^4}\theta \cdot t\left( {\dfrac{1}{{R_{{\rm{m}}1}^2}} + \dfrac{1}{{R_{{\rm{m}}2}^2}}} \right)\\ {\Lambda _5} = \dfrac{{\left( {1 + \nu } \right){R_6}\left[ {\left( {1 - 2\nu } \right)R_6^2 + R_7^2} \right]}}{{{E_{\rm{S}}}\left( {R_6^2 - R_7^2} \right)}}\\ {\Lambda _6} = \dfrac{{2\left( {1 - {\nu ^2}} \right){P_{{\rm{out}}}}R_6^2R_7^2}}{{{E_{\rm{S}}}\left( {R_6^2 - R_7^2} \right)}} + \nu \dfrac{{{R_6}\Delta L}}{L}\\[-14pt] \end{array} \right.$

(1)

式中：u_Ri为径向位移量；β为考虑间隙时的折减系数；E为钢带弹性模量；θ为钢带缠绕螺旋角度；L为管道长度；∆L为拉伸长度；n为同一层增强层中钢带的条数；b为带宽；R_mi为第i层钢带增强层的平均缠绕半径；t为钢带厚度；R₆为内层PE管外半径；R₇为外层PE管内半径；E_S为PE材料在当前加载步下的割线模量。

PE管的轴向拉力F_PEi为

${F_{{\rm{PE}}i}} = \frac{{{E_{\rm{S}}}{A_{0i}}\Delta L}}{{\Delta L + L}}$

(2)

式中，A_0i为PE管截面初始面积。

钢带缠绕增强复合管总轴向拉力F_T可看作管道各层贡献值的累加，即

${F_{\rm{T}}} = \Sigma {F_{{\rm{PE}}}} + \Sigma {F_{{\rm{steel}}}}$

(3)

图2为钢带缠绕增强复合管数值模型与实验及解析解对比。可知，将数值计算模型与文献[8]的试验结果及文献[24]的解析模型进行对比，三者变化趋势一致。同时，本文数值计算模型比解析模型更接近试验值，这是由于解析模型未考虑层与层之间的摩擦作用及螺旋钢带自身弯曲变化，即仅考虑钢带沿带长度方向的轴向变形。因此，该数值计算模型较为可靠。

图 2 钢带缠绕增强复合管数值模型与试验及解析解对比

Figure 2. Comparison of numerical model, experimental and analytical model results of reinforced composite pipe wound with steel strip

下载: 全尺寸图片幻灯片

2. 不同组合载荷下钢带缠绕增强复合管的力学性能

为研究由拉伸、内外压和弯曲载荷组合的复杂载荷下带缠绕增强复合管的力学性能，其组合类型为：内外压加拉伸、内外压加弯曲、内外压加弯曲及拉伸，同时与纯拉伸和纯弯曲载荷条件进行对比。由于海底工况复杂，带缠绕增强复合管受载具有不确定性，因此本文选取的加载路径为在同一分析步中同时施加内外压、拉伸或弯曲载荷。承载能力可通过管道屈曲时的载荷大小判定，载荷越大，承载性能越好。钢带缠绕增强复合管的拉伸刚度为

$k = \frac{F}{x}$

(4)

式中：k为拉伸刚度；F为轴向拉力；x为轴向位移。

钢带缠绕增强复合管的弯曲刚度为

$m = \frac{M}{\alpha }$

(5)

式中：m为弯曲刚度；M为弯矩；α为弯曲角度。

图3为钢带缠绕增强复合管轴向拉力和拉伸量的关系曲线。可知，在弹性阶段(AB、AC、AD段)，钢带缠绕增强复合管的拉伸刚度不变。在BE、DF、CG段，钢带缠绕增强复合管的拉伸刚度随伸长量增大而减小，非线性特征明显，将该阶段定义为过渡阶段。而EH、FI、GJ段则为整体的屈服阶段。曲线Ⅰ(内压为1 MPa、外压为3 MPa)和曲线Ⅱ(内压为2 MPa、外压为3 MPa)的拉伸刚度明显小于纯拉伸情况，这是由外压大于内压，压差引起泊松效应(一端固定条件下，钢带缠绕增强复合管因挤压而径向收缩，又因整体体积不变，钢带缠绕增强复合管将沿自由端方向伸长)造成的。在曲线Ⅰ基础上，对自由端施加0.2 rad的转角位移，钢带缠绕增强复合管被拉伸约至77 mm时其拉力急剧下降，此时钢带缠绕增强复合管失效。可以看出，弯曲载荷对钢带缠绕增强复合管拉伸刚度影响较小，但会降低钢带缠绕增强复合管屈曲时的临界拉力，即抗拉承载能力降低。

图 3 不同拉伸载荷作用下钢带缠绕增强复合管的力学性能

Figure 3. Mechanical properties of reinforced composite pipe wound with steel strip under different tensile loads

下载: 全尺寸图片幻灯片

图4为钢带缠绕增强复合管的弯矩和弯曲角度关系曲线。可知，曲线Ⅰ(内压为1 MPa、外压为3 MPa)和曲线Ⅱ(内压为2 MPa、外压为3 MPa)的钢带缠绕增强复合管弯曲刚度明显小于纯弯曲情况。这是由于钢带缠绕增强复合管不受内外压作用时，层间挤压较小，最大静摩擦力小；在弯曲过程中各层易产生相对滑移，滑动摩擦力在一定程度上阻碍钢带缠绕增强复合管变形，使钢带缠绕增强复合管产生更大弯矩，即迟滞效应。同理，钢带缠绕增强复合管承受内外压时，层间摩擦力增强，无滑移现象，钢带缠绕增强复合管整体性提高。在曲线Ⅰ基础上，钢带缠绕增强复合管被拉伸至60 mm，轴向拉力所形成的弯矩与初始弯矩叠加，使在相同弯曲形变下钢带缠绕增强复合管弯曲刚度大幅提高，柔性降低。

图 4 不同弯曲载荷作用下钢带缠绕增强复合管的力学性能

Figure 4. Mechanical properties of reinforced composite pipe wound with steel strip under different bending loads

下载: 全尺寸图片幻灯片

当钢带缠绕增强复合管承受较大内外压时，虽然钢带缠绕增强复合管整体性增强，但由于钢带缠绕增强复合管各层力学性能不同，形变过程中外层PE管易提前进入屈服阶段，使钢带缠绕增强复合管整体弯曲刚度下降，管端弯矩出现极大值，如曲线Ⅰ和Ⅱ所示。

3. 复杂载荷下钢带缠绕增强复合管各层力学性能对比

3.1 内层和外层PE管的力学性能

图5为内层和外层PE管在纯拉伸和组合拉伸(包含内外压和弯曲，且以拉伸载荷为主)载荷作用下的应力云图。可见，纯拉伸作用下应力沿管道分布较均匀，两端应力小于中间段。内层PE管出现螺旋状高应力区，这是由于拉伸过程中钢带边缘对其径向挤压。而在组合拉伸作用下，相同拉伸长度的内层和外层PE管在自由端附近产生严重的屈曲破坏，进入失效状态。

图 5 内层和外层聚乙烯(PE)管在纯拉伸和组合拉伸下的应力分布

Figure 5. Stress distributions of inner and outer polyethylene (PE) pipes under pure tensile and combined tensile loads

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图6为内层和外层PE管在纯拉伸和组合拉伸作用下应力及应变随拉伸量的变化。由图6(a)可知，纯拉伸载荷作用时，轴向位移为0~90 mm范围内的应变呈线性变化，复合管处于弹性状态，且内层和外层PE管应变基本一致。在组合拉伸下，内层和外层PE管在拉伸至77 mm时应变急剧增大，达到屈服极限，开始产生塑性变形，且外层PE管应变大于内层PE管。由图6(b)可知，当拉伸至76.5 mm时，外层PE管的最大Mises应力达到22.60 MPa，内层PE管为21.51 MPa，进一步说明在组合拉伸的条件下，外层PE管力学响应较内层PE管更为敏感。

图 6 内层和外层PE管在纯拉伸和组合拉伸作用下的应力和应变

Figure 6. Stress and strain of inner and outer PE pipes under pure tensile and combined tensile loads

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外层PE管应力分布如图6(a)内图所示。可知，在拉伸过程中管道自由端上部出现高应力区，外层PE管螺旋状高应力区的应力值逐渐增大，最终在拉伸约至77 mm时，外层PE管在自由端附近发生屈曲失效。

图7为内层和外层PE管在纯弯曲和组合弯曲(包含内外压和拉伸，且以弯曲载荷为主)作用下的应力云图。可见，在纯弯曲作用下，高应力区出现在管道固定端附近上部。而在组合弯曲作用下的高应力区出现在管道自由端附近，并发生屈曲破坏。同时外层PE管应力分布较内层PE管更具规律性。

图 7 内层和外层PE管在纯弯曲和组合弯曲下的应力分布

Figure 7. Stress distribution of inner and outer PE pipes under pure bending loads and combined bending loads

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图8为内层和外层PE管在纯弯曲和组合弯曲作用下的应力和应变随弯曲角度的变化。由图8(a)可知，在纯弯曲作用下，内层和外层PE管均处于弹性阶段；在组合弯曲载荷作用下，内层和外层PE管的应变在弯曲角度分别为0.24 rad和0.25 rad时急剧增加，外层PE管提前失效。由图8(b)可知，无论是在纯弯曲载荷作用下还是组合弯曲载荷作用下，外层PE管的Mises应力始终大于内层PE管。

图 8 内层和外层PE管在纯弯曲和组合弯曲作用下应力和应变

Figure 8. Stress and strain of inner and outer PE pipes under pure bending and combined bending loads

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外层PE管应力分布如图8(a)内图所示。可知，钢带缠绕增强复合管变形过程中外层PE管的高应力区不断向自由端集中，并在其附近发生屈曲破坏。管道整体曲率半径非常大，说明在组合弯曲载荷作用下钢带缠绕增强复合管弯曲刚度大幅度提高，柔性降低。

3.2 钢带增强层的力学性能

图9为组合拉伸载荷和组合弯曲载荷作用下内层缠绕钢带的应力云图。可见，钢带在组合拉伸载荷和组合弯曲载荷作用下应力分布几乎一致。应力沿轴向方向呈非均匀分布，这是由于边界条件的非线性即端部效应，钢带在边缘部分出现应力集中造成的。同时，应力集中区域沿某一路径具有对称性。创建相应路径及节点编号1~7，提取一组单元在同一时刻对应节点的Mises应力，如图9所示。由文献[8]可知，纯拉伸下内层钢带对称应力的路径平行于带宽分布，而组合拉伸载荷和组合弯曲载荷作用下的路径发生偏移，说明复杂载荷会改变内层钢带对称应力分布路径。

图 9 内层缠绕钢带应力云图及节点Mises应力

Figure 9. Stress cloud diagram of inner wound steel strip and Mises stress of nodes

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4. 参数敏感性分析

4.1 钢带螺旋角度

选取钢带缠绕增强复合管中钢带增强层的三种螺旋角度(±54.7°、±60.5°、±67.7°)进行分析。图10为组合拉伸载荷作用下螺旋角对钢带缠绕增强复合管拉伸性能的影响。可见，随着螺旋角度增大，由于未发生层间相对滑动，钢带缠绕增强复合管在弹性阶段的拉伸刚度几乎不发生变化；在过渡及屈服阶段，钢带缠绕增强复合管的拉伸刚度增大，柔性降低，这是由于螺旋角度的增大，增加了单位轴向长度内钢带缠绕圈数，导致钢带覆盖率提高，总摩擦力增大，钢带缠绕增强复合管各层之间不易产生滑移。随着螺旋角增大，钢带缠绕增强复合管屈曲时的临界拉力增大，抗拉承载能力提高。

图 10 组合拉伸载荷作用下螺旋角对钢带缠绕增强复合管拉伸性能影响

Figure 10. Effect of helix angles on tensile properties of reinforced composite pipe wound with steel strip under combined tensile load

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图11为组合弯曲载荷作用下螺旋角对钢带缠绕增强复合管弯曲性能影响。可见，随着螺旋角度增大，钢带缠绕增强复合管在弹性阶段的弯曲刚度基本不变；在屈服阶段，钢带缠绕增强复合管弯曲刚度随螺旋角增大而增大，柔性降低，这是由于螺旋角度越大，在保持钢带宽度不变条件下，单位轴向长度内钢带缠绕圈数增大，即钢带覆盖率越高，钢带缠绕增强复合管整体刚度越大；钢带缠绕增强复合管屈曲时的临界弯矩呈非单调变化，存在极大值，当弯曲角度为0.215 rad时，螺旋角为60.5°的钢带缠绕增强复合管弯矩为697 kN·m，载荷达到屈曲临界值，而螺旋角为54.7°的钢带缠绕增强复合管仍处于屈服阶段，螺旋角为67.7°的钢带缠绕增强复合管早已失效。

图 11 组合弯曲载荷作用下螺旋角对钢带缠绕增强复合管弯曲性能影响

Figure 11. Effect of helix angles on bending properties of reinforced composite pipe wound with steel strip under combined bending load

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4.2 层间摩擦系数

图12为组合拉伸载荷作用下摩擦系数对钢带缠绕增强复合管拉伸性能的影响。可知，在组合拉伸载荷作用下，随着摩擦系数增大，钢带缠绕增强复合管在弹性阶段轴向拉伸刚度基本不变，体现了较强整体性；在过渡阶段，钢带缠绕增强复合管拉伸刚度提高，柔性降低，这是由于摩擦系数的增大提高了层间滑动摩擦力，迟滞效应更加明显；钢带缠绕增强复合管屈曲时的临界拉力增大，抗拉承载能力提高，即当摩擦系数为0.2时，钢带缠绕增强复合管在拉伸至77 mm时失效，而对于其他情况，其失效时的拉伸量均小于77 mm。

图 12 组合拉伸载荷作用下摩擦系数对钢带缠绕增强复合管拉伸性能的影响

Figure 12. Effect of friction coefficients on tensile properties of reinforced composite pipe wound with steel strip under combined tensile load

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图13为组合弯曲下摩擦系数对钢带缠绕增强复合管弯曲性能影响。可见，随着摩擦系数增大，弹性阶段的钢带缠绕增强复合管与组合拉伸载荷作用下刚度的变化规律类似。钢带缠绕增强复合管屈曲时的临界弯矩逐渐增大，抗弯承载能力提高。

图 13 组合弯曲下摩擦系数对钢带缠绕增强复合管弯曲性能影响

Figure 13. Effect of friction coefficients on bending properties of reinforced composite pipe wound with steel strip under combined bending load

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5. 结论

(1)压差(外压大于内压，且≤2 MPa)越大，钢带缠绕增强复合管柔性越高；钢带缠绕增强复合管弯矩存在极大值。与纯拉伸作用相比，组合拉伸载荷作用时钢带缠绕增强复合管屈服时的临界拉力降低，抗拉承载能力降低；与纯弯曲作用相比，组合弯曲载荷作用时钢带缠绕增强复合管柔性大幅降低。

(2)复杂载荷作用的高应力区出现在钢带缠绕增强复合管自由端附近，并在此处发生屈曲失效，且外层聚乙烯(PE)管的应变大于内层PE管；而在纯弯曲载荷作用下，高应力区出现在钢带缠绕增强复合管的固定端，纯拉伸载荷作用下应力分布较均匀；复杂载荷会改变内层钢带对称应力的分布路径。

(3)复杂载荷作用下，钢带螺旋角度及摩擦系数越大，钢带缠绕增强复合管柔性越低。在组合拉伸载荷作用下，增大钢带螺旋角及层间摩擦系数，钢带缠绕增强复合管屈曲时的临界拉力增大，承载能力提高。在组合弯曲载荷作用下，螺旋角增大使钢带缠绕增强复合管屈曲时的临界弯矩呈非单调变化，存在极大值；层间摩擦系数越大，临界弯矩越大，钢带缠绕增强复合管的抗弯承载能力提高。

图 1 SiO₂-RDP/(PC-ABS)阻燃合金的热释放速率、质量损失、总热释放量、总生烟量、烟释放速率、CO生成率和CO₂生成率的曲线

Figure 1. Heat release rate, mass loss, total heat release, total smoke release, smoke production rate, volume fraction of CO and volume fraction of CO₂ curves of SiO₂-RDP/PC-ABS flame retardant blends

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图 2 10RDP/(PC-ABS)((a)~(c))、1SiO₂-10RDP/(PC-ABS)((d)~(f))和1SiO₂/(PC-ABS)((g)~(i))阻燃合金的燃烧残炭形貌

Figure 2. Morphologies of char residues of 10RDP/(PC-ABS)((a)–(c)), 1SiO₂-10RDP/(PC-ABS)((d)–(f)) and 1SiO₂/(PC-ABS)((g)–(i)) flame retardant blends

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图 3 10RDP/(PC-ABS)(a)、1SiO₂-10RDP/(PC-ABS)(b)和1SiO₂/(PC-ABS)(c)阻燃合金燃烧残炭的SEM图像

Figure 3. SEM images of char residues of 10RDP/(PC-ABS)(a), 1SiO₂-10RDP/(PC-ABS)(b) and 1SiO₂/(PC-ABS)(c) flame retardant blends

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图 4 1SiO₂-10RDP/(PC-ABS)阻燃合金燃烧残炭表面的P元素(a)和Si元素(b)分布

Figure 4. P distribution(a) and Si distribution(b) of char residues of 1SiO₂-10RDP/(PC-ABS) flame retardant blends

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图 5 SiO₂-RDP-MBS/(PC-ABS)阻燃合金的力学性能

Figure 5. Mechanical properties of SiO₂-RDP-MBS/(PC-ABS) flame retardant blends

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图 6 PC-ABS ((a)、(b))、10RDP/(PC-ABS) ((c)、(d))、1SiO₂-10RDP/(PC-ABS) ((e)、(f))和1SiO₂-10RDP-20MBS/(PC-ABS)((g)、(h))阻燃合金缺口冲击断面的SEM图像

Figure 6. SEM images of notched impact cross section of PC-ABS ((a),(b)), 10RDP/(PC-ABS) ((c),(d)), 1SiO₂-10RDP/(PC-ABS) ((e),(f)) and 1SiO₂-10RDP-20MBS/(PC-ABS) ((g),(h)) flame retardant blends

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表 1 SiO₂-间苯二酚-双(二苯基磷酸酯)-甲基丙烯酸甲酯-丁二烯-苯乙烯/(聚碳酸酯-丙烯腈-丁二烯-苯乙烯共聚物)(SiO₂-RDP-MBS/(PC-ABS))阻燃合金配比

Table 1 Formulations of SiO₂-resorcinol bis(diphenylphosphate)-methyl methacrylate-butadiene-styrene/(polycarbonate-acrylonitrile-butadiene-styrene)(SiO₂-RDP-MBS/(PC-ABS)) flame retardant blends wt%

Sample	PC	ABS	RDP	SiO₂	PTFE	MBS
10RDP/(PC-ABS)	62.7	26.9	10	—	0.4	—
0.5SiO₂-10RDP/(PC-ABS)	62.4	26.7	10	0.5	0.4	—
1SiO₂-10RDP/(PC-ABS)	62.0	26.6	10	1	0.4	—
2SiO₂-10RDP/(PC-ABS)	61.3	26.3	10	2	0.4	—
3SiO₂-10RDP/(PC-ABS)	60.6	26.0	10	3	0.4	—
4SiO₂-10RDP/(PC-ABS)	59.9	25.7	10	4	0.4	—
5SiO₂-10RDP/(PC-ABS)	58.9	25.2	10	5	0.4	—
6SiO₂-10RDP/(PC-ABS)	58.5	25.1	10	6	0.4	—
7SiO₂-10RDP/(PC-ABS)	57.8	24.8	10	7	0.4	—
1SiO₂/(PC-ABS)	69.0	29.6	—	1	0.4	—
1SiO₂-10RDP-5MBS/(PC-ABS)	58.5	25.1	10	1	0.4	5
1SiO₂-10RDP-10MBS/(PC-ABS)	55.0	23.6	10	1	0.4	10
1SiO₂-10RDP-15MBS/(PC-ABS)	51.5	22.1	10	1	0.4	15
1SiO₂-10RDP-20MBS/(PC-ABS)	48.0	20.6	10	1	0.4	20
1SiO₂-10RDP-25MBS/(PC-ABS)	44.5	19.1	10	1	0.4	25
Note: PTFE—Polytetrafluoroethylene.

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表 2 SiO₂-RDP-MBS/(PC-ABS)阻燃合金的垂直燃烧 (UL94) 测试结果

Table 2 Vertical combustion (UL94) results of SiO₂-RDP-MBS/(PC-ABS) flame retardant blends

Sample	t₁/s	t₂/s	t₁+t₂/s	Dripping	UL94
10RDP/(PC-ABS)	12.1	20.3	32.4	N	V-1
0.5SiO₂-10RDP/(PC-ABS)	21.4	24.5	45.9	N	V-1
1SiO₂-10RDP/(PC-ABS)	3.1	8.9	12.0	N	V-0
2SiO₂-10RDP/(PC-ABS)	11.3	31.4	42.7	N	V-1
3SiO₂-10RDP/(PC-ABS)	16.8	26.1	42.9	N	V-1
4SiO₂-10RDP/(PC-ABS)	25.7	38.7	64.4	N	V-1
5SiO₂-10RDP/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
6SiO₂-10RDP/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
7SiO₂-10RDP/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
1SiO₂/(PC-ABS)	>30.0	>60.0	>60.0	N	No-rating
1SiO₂-10RDP-5MBS/(PC-ABS)	16.2	24.5	40.7	N	V-1
1SiO₂-10RDP-10MBS/(PC-ABS)	31.3	50.4	81.7	N	V-2
1SiO₂-10RDP-15MBS/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
1SiO₂-10RDP-20MBS/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
1SiO₂-10RDP-25MBS/(PC-ABS)	>30.0	>60.0	>60.0	Y	No-rating
Notes: t₁—Self-extinguishing time after the first ignition; t₂—Self-extinguishing time after the second ignition;Y—Yes; N—No.

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表 3 SiO₂-RDP/(PC-ABS)阻燃合金的锥形量热测试结果

Table 3 Cone data for SiO₂-RDP/(PC-ABS) flame retardant blends

Sample	10RDP/(PC-ABS)	1SiO₂-10RDP/(PC-ABS)	1SiO₂/(PC-ABS)
t_ign/s	41.5±0.5	42.0±1.0	38.5±0.5
t_PHRR/s	155.0±5.0	167.5±2.5	70±0.1
PHRR/(kW·m⁻²)	444.8±22.3	379.1±5.4	566.1±16.8
THR/(MJ·m⁻²)	68.2±0.4	70.4±1.5	92.0±1.3
AHRR/(kW·m⁻²)	135.9±2.1	142.7±0.6	224.3±2.3
AMLR/(g·s⁻¹)	0.060±0.001	0.062±0.002	0.082±0.002
AEHC/(MJ·kg⁻¹)	19.9±0.1	20.4±0.6	24.5±0.4
ASEA/(m²·kg⁻¹)	1 048.1±35.8	1 068.0±15.1	838.2±45.4
ACOY/(kg·kg⁻¹)	0.146±0.001	0.156±0.002	0.083±0.001
ACO₂Y/(kg·kg⁻¹)	1.383±0.001	1.382±0.014	1.738±0.041
TSR/(m²·m⁻²)	3 592.1±102.9	3 682.1±85.3	3 156.6±182.8
CHR/%	6.86±0.03	6.94±0.53	5.76±0.98
FGI/(kW·m⁻²·s⁻¹)	2.87	2.26	8.09
FPI/(m²·s·kW⁻¹)	0.093	0.110	0.068
Notes: PHRR—Peak heat release rate; THR—Total heat release at 600 s; AHRR—Average heat release rate; AMLR—Average mass loss rate; AEHC—Average effective heat of combustion; ASEA—Average specific extinction area; ACOY—Average yield of CO; ACO₂Y—Average yield of CO₂; TSR—Total smoke release; CHR—Char residue; FGI—Fire spread index; FPI—Fire performance index; t_ign—Time to ignition; t_PHRR—Time to PHRR.

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表 4 10RDP/(PC-ABS)、1SiO₂-10RDP/(PC-ABS)和1SiO₂/(PC-ABS)阻燃合金锥形量热测试后残炭的EDS分析

Table 4 EDS analysis of char residues of 10RDP/(PC-ABS), 1SiO₂-10RDP/(PC-ABS) and 1SiO₂/(PC-ABS) flame retardant blends after Cone tests

Sample	Element/at%
Sample	C	O	P	Si
1SiO₂/(PC-ABS)	83.89	16.09	—	0.03
10RDP/(PC-ABS)	79.44	18.02	2.54	—
1SiO₂-10RDP/(PC-ABS)	54.17	36.71	7.24	1.88

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表 5 SiO₂-RDP-MBS/(PC-ABS)阻燃合金的缺口冲击强度、拉伸强度、断裂伸长率和弹性模量

Table 5 Izod impact strength、tensil strength、elongation at break and tensile modulus of SiO₂-RDP-MBS/(PC-ABS) flame retardant blends

Sample	Izod impact strength/(kJ·m⁻²)	Tensile strength/MPa	Elongation at break/%	Tensile modulus/MPa
10RDP/(PC-ABS)	8.6±2.4	51.4±2.8	19.2±5.1	838.7±146.2
1SiO₂-10RDP/(PC-ABS)	6.0±1.1	50.9±3.7	18.6±3.1	893.2±168.4
1SiO₂-10RDP-5MBS/(PC-ABS)	8.1±0.6	47.8±2.4	14.9±3.1	372.2±366.1
1SiO₂-10RDP-10MBS/(PC-ABS)	13.1±3.5	39.8±2.9	25.1±6.8	504.1±84.6
1SiO₂-10RDP-15MBS/(PC-ABS)	15.4±1.5	36.9±2.9	37.9±5.8	406.2±178.5
1SiO₂-10RDP-20MBS/(PC-ABS)	26.8±3.5	32.3±3.3	29.1±4.1	414.9±105.9
1SiO₂-10RDP-25MBS/(PC-ABS)	23.1±0.9	27.7±2.6	24.5±8.1	468.1±149.1

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