CN110655334B - 一种非均相固化树脂体系的微脱粘试样制备方法 - Google Patents

一种非均相固化树脂体系的微脱粘试样制备方法 Download PDF

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CN110655334B
CN110655334B CN201910933132.2A CN201910933132A CN110655334B CN 110655334 B CN110655334 B CN 110655334B CN 201910933132 A CN201910933132 A CN 201910933132A CN 110655334 B CN110655334 B CN 110655334B
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郭妙才
李亚锋
洪旭辉
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AVIC BASIC TECHNOLOGY RESEARCH INSTITUTE
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Abstract

本发明涉及一种非均相固化树脂体系的微脱粘试样制备方法,尤其适用于具有非均相固化体系的树脂和纤维之间的界面剪切强度的测试,采用树脂预聚合处理的方法,提高树脂内部的均一性分布,控制粘度和微球大小,得到测试稳定性良好的试样,显著提高了测试试样的结果稳定性和准确性,可准确反映该树脂体系和纤维之间的界面结合能力。

Description

一种非均相固化树脂体系的微脱粘试样制备方法
技术领域
本发明涉及复合材料的测试技术领域,特别是涉及一种非均相固化树脂体系的微脱粘试样制备方法。
背景技术
连续纤维增强的树脂基复合材料与传统金属材料相比,具有更小的密度和更高的比强度、比刚度,在航空航天、石油、运输、体育器材等领域具有越来越广泛的应用。对于连续纤维增强的树脂基复合材料,纤维和树脂的界面起到纤维和树脂之间的连接和应力传递,是复合材料静态力学性能和疲劳力学性能的重要影响因素,界面剪切强度也是界面性能的最为重要的指标之一,如何准确得到界面剪切强度,是材料研发和性能评估的关键。
微脱粘法是评估界面剪切强度的一种重要方法,这种方法首先由Miller等于1987年提出来,它是将纤维垂直埋入一非常小呈对称状的树脂滴中,如图1所示,实验方法与拔出实验相似,很容易测出拔出力的大小,通过粘结长度或粘结面积估算出纤维一树脂界面间的粘结强度r值。然而目前这种方法测试误差较大,其原因之一是制样过程中的控制。尤其是当树脂为潜伏型固化的树脂体系时,由于固化剂体系的非均相分布,造成微脱粘试样内部固化程度的严重不均,最后得到的界面剪切强度不仅较低,而且具有很大的离散,如此评估单位给出的数据就无法用作有效的参考。
综上,为了避免以上问题,需要发展一种非均相固化树脂体系的微脱粘试样制备方法,实现界面剪切强度的低误差测试。
发明内容
(1)要解决的技术问题
本发明针对现有技术的缺陷,提出了一种非均相固化树脂体系的微脱粘试样制备方法,即通过预聚和均匀度、粘度控制,消除微脱粘试样制样中的诸多不确定因素,实现稳定、低离散的制样和测试结果。
(2)技术方案
本发明的技术方案的核心是即通过树脂的均匀性和粘度控制,通过预聚法减少非均相固化树脂体系中的组分的非均匀程度,消除微脱粘试样制样中的诸多不确定因素,同时避免溶液等分散剂对界面的影响,实现具有稳定、低离散的界面剪切强度值的微脱粘试样的制样。
本发明中非均相固化树脂体系的微脱粘试样制备方法,包括:将非均相固化树脂在低于其固化温度20~50℃的温度下预聚20~90min,并控制该温度下预聚树脂的粘度为0.5~8Pa.s,随后将预聚后的树脂快速涂于纤维单丝上形成微球,再于该非均相固化树脂的固化条件下固化得到悬挂固化树脂微球的纤维丝,筛选直径大小为40~70μm的微球作为微脱粘试样。
进一步的,所述预聚后的树脂中未溶解组分的平均团聚粒径小于3μm。
进一步的,检测平均团聚粒径的方法为激光光散射法
进一步的,所述非均相固化树脂为具有潜伏型固化体系的环氧树脂、非均相的双马来酰亚胺树脂中的任意一种。
进一步的,所述纤维单丝为碳纤维单丝、玻璃纤维单丝、芳纶纤维单丝中的任意一种。
优选地,当纤维单丝为碳纤维单丝时,选用直径为40~55μm的微球作为微脱粘试样。
优选地,当纤维单丝为玻璃纤维单丝时,选用直径为55~65μm的微球作为微脱粘试样。
优选地,当纤维单丝为芳纶纤维单丝时,选用直径为55~65μm的微球作为微脱粘试样。
进一步的,树脂固化完成后,冷却至60℃以下时,按照纤维单丝上微球的粒径进行筛选。
(3)有益效果
针对现有技术中微脱粘法测试界面剪切强度数据误差较大的问题,尤其对于非均相固化树脂体系难以准确测试界面剪切强度的问题,提出本申请的方法制备微脱粘试样,得到的微球脱粘试样用于测试界面剪切强度,不仅误差较小,而且更能反映纤维和树脂之间真实的界面剪切强度。
通过本申请的制样处理方法,剪切强度与直径的依赖性关系消失,在整个直径筛选范围内分布均一,更真实地体现了纤维-树脂之间的界面剪切强度。通过预聚均匀化解决了试样内部各物质分配不均的问题,通过粘度控制使试样保持符合真实条件下的界面浸润和物质二次分配,通过合理的纤维直径筛选避免了因纤维断裂、微球破坏造成的误差。
附图说明
图1是微脱粘法实施操作示意图。
图2是实施例1和对比例1中双氰胺固化体系的环氧树脂界面剪切强度与微球直径的关系。
具体实施方式
下面结合附图和实施例对本发明的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本发明的原理,但不能用来限制本发明的范围,即本发明不限于所描述的实施例,在不脱离本发明的精神的前提下覆盖了零件、部件和连接方式的任何修改、替换和改进。
需要说明的是,在不冲突的情况下,本申请中的实施例及实施例中的特征可以相互组合。下面将参照附图并结合实施例来详细说明本申请。
实施例1
一种非均相固化树脂体系的微脱粘试样制备方法,包括以下操作步骤:
(1)将具有双氰胺固化体系的环氧树脂在140℃下预先聚合70min,或者在152℃下预先聚合25min,预聚结束后,相应温度下预聚树脂的粘度为1.5Pa.s,激光光散射法检测树脂中的颗粒聚集体大小约为1.2μm;
(2)在相应温度下将预聚合树脂快速涂于玻璃纤维上,涂抹形成微球,再将形成的液体微球在树脂固化所需的固化条件下(177℃/120min)固化得到带有固化树脂微球的玻璃纤维单丝,固化完成后冷却到60℃以下取出,筛选直径大小为60±5μm的微球作为测试试样进行微脱粘测试。
本实施例得到微脱粘试样,用于测试界面剪切强度具有良好的测试稳定性,破坏模式符合测试原理,可以准确反映树脂和纤维之间的界面结合强度。
实施例2
一种非均相固化树脂体系的微脱粘试样制备方法,包括以下操作步骤:
(1)将具有双氰胺/聚脲固化体系的环氧树脂在80℃下预先聚合70min,或者在90℃下预先聚合35min,或在95℃下预先聚合20min,预聚结束后,该温度下预聚树脂的粘度分别为0.8Pa.s、1.3Pa.s和2.5Pa.s,激光光散射法检测树脂中的颗粒聚集体大小分别为2.2μm、1.2μm和0.8μm;
(2)在相应温度下将预聚合结束后的树脂快速涂于碳纤维上,形成微球,再将形成的液体微球在树脂固化所需的固化条件(120℃/120min)下固化得到带有固化树脂微球的碳纤维单丝,固化完成后冷却到60℃以下取出,筛选尺寸大小为45±5μm的微球作为测试试样进行微脱粘测试。
本实施例得到微脱粘试样,用于测试界面剪切强度具有良好的测试稳定性,破坏模式符合测试原理,可以准确反映树脂和纤维之间的界面结合强度。
实施例3
一种非均相固化树脂体系的微脱粘试样制备方法,包括以下操作步骤:
(1)将具有中温固化三氟化硼-单胺固化体系的环氧树脂在85℃下预先聚合25min,预聚结束后,该温度下预聚树脂的粘度约2.1Pa.s,激光光散射法检测树脂中的颗粒聚集体尺寸为0.6μm;
(2)该温度下将预处理树脂快速涂于芳纶纤维上,形成微球,再将形成的液体微球在树脂固化所需的固化条件(130℃/120min)下固化得到带有固化树脂微球的芳纶纤维单丝,固化完成后冷却到60℃以下取出,筛选尺寸大小为58~75μm的微球作为测试试样进行微脱粘测试。
对比例1
一种非均相固化树脂体系的微脱粘试样制备方法,是将具有中温固化双氰胺/聚脲固化体系的环氧树脂快速涂于玻璃纤维上,涂抹形成微球,再将形成的液体微球在120℃的温度下固化处理120min,固化得到带有固化树脂微球的玻璃纤维单丝,固化完成后冷却到60℃以下取出,筛选不同直径大小的微球作为测试试样进行微脱粘测试。
如图2所示,采用对比例1方法制样并测试时,随着微脱粘试样的微球直径逐渐增大,测试得到的界面剪切强度也逐渐增大,存在着显著的差异,因此给测试带来了巨大的误差,当微球直径较小时(介于58~80μm),测试值显著偏低,而当微球直径偏大时(>=80μm),测试纤维断裂严重,得到的测试值也是不准确的,当微球直径小于58μm时,测试值也显著偏低且微球破裂严重,此时却往往被各测试单位凭借测试通常试样的经验当作真实的界面剪切强度值,但经断面研究发现此时断裂发生在基质树脂内,而非纤维与树脂的界面,不能作为该体系的界面剪切强度。
通过实施例2的制样处理方法,剪切强度与直径的依赖性关系消失,在整个直径筛选范围内分布均一,断裂模式正确,更真实地体现了纤维-树脂之间的界面剪切强度。通过预聚均匀化解决了试样内部各物质分配不均的问题,通过粘度控制使试样保持符合真实条件下的界面浸润和物质二次分配,通过合理的纤维直径筛选避免了因纤维断裂、微球破坏造成的误差。
实施例2的优点和特点在于,可以准确测试具有非均相固化体系的树脂和纤维的界面剪切强度,得到的界面剪切强度可靠准确,测试界面强度相差较小的不同树脂/纤维体系时,也具有较好的可比性。
以上所述仅为本申请的实施例而已,并不限制于本申请。在不脱离本发明的范围的情况下对于本领域技术人员来说,本申请可以有各种更改和变化。凡在本申请的精神和原理之内所作的任何修改、等同替换、改进等,均应包含在本申请的权利要求范围内。

Claims (7)

1.一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,包括:将非均相固化树脂在低于其固化温度20~50℃的温度下预聚20~90min,并控制该温度下预聚树脂的粘度为0.5~8Pa.s,所述预聚后的非均相固化树脂中未溶解组分的平均团聚粒径小于3μm,检测平均团聚粒径的方法为激光光散射法,随后将预聚后的树脂快速涂于纤维单丝上形成微球,再于该非均相固化树脂的固化条件下固化得到悬挂固化树脂微球的纤维丝,筛选直径大小为40~70μm的微球作为微脱粘试样。
2.根据权利要求1所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,所述非均相固化树脂为具有潜伏型固化体系的环氧树脂。
3.根据权利要求1所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,所述纤维单丝为碳纤维单丝、玻璃纤维单丝、芳纶纤维单丝中的任意一种。
4.根据权利要求3所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,当纤维单丝为碳纤维单丝时,选用直径为40~55μm的微球作为微脱粘试样。
5.根据权利要求3所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,当纤维单丝为玻璃纤维单丝时,选用直径为55~65μm的微球作为微脱粘试样。
6.根据权利要求3所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,当纤维单丝为芳纶纤维单丝时,选用直径为55~65μm的微球作为微脱粘试样。
7.根据权利要求1所述的一种非均相固化树脂体系的微脱粘试样制备方法,其特征在于,树脂固化完成后,冷却至60℃以下时,按照纤维单丝上微球的粒径进行筛选。
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015181516A1 (en) * 2014-05-28 2015-12-03 Bae Systems Plc Improved structural health monitoring
CN105547851A (zh) * 2015-12-09 2016-05-04 哈尔滨工业大学 一种紧凑型复合材料界面剪切强度测试装置及利用其测试复合材料界面剪切强度的方法
CN108070223A (zh) * 2017-12-29 2018-05-25 陕西科技大学 一种基于温度处理碳纤维提高树脂基复合材料界面粘结性能的方法
CN109596464A (zh) * 2018-12-27 2019-04-09 北京航空航天大学 一种碳纳米管表面改性纤维的界面性能测试方法
CN109632636A (zh) * 2019-01-09 2019-04-16 南京航空航天大学 高通量测试纤维与树脂微观界面性能的制冷装置及方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015181516A1 (en) * 2014-05-28 2015-12-03 Bae Systems Plc Improved structural health monitoring
CN105547851A (zh) * 2015-12-09 2016-05-04 哈尔滨工业大学 一种紧凑型复合材料界面剪切强度测试装置及利用其测试复合材料界面剪切强度的方法
CN108070223A (zh) * 2017-12-29 2018-05-25 陕西科技大学 一种基于温度处理碳纤维提高树脂基复合材料界面粘结性能的方法
CN109596464A (zh) * 2018-12-27 2019-04-09 北京航空航天大学 一种碳纳米管表面改性纤维的界面性能测试方法
CN109632636A (zh) * 2019-01-09 2019-04-16 南京航空航天大学 高通量测试纤维与树脂微观界面性能的制冷装置及方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
非均相固化体系对复合材料树脂微观力学均匀性的影响;郭妙才等;《材料工程 Journal of Materials Engineering》;20181031;第46卷(第10期);第142-148页 *

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