普丹丹 周涵 普慶
摘要:為探究改性處理對(duì)滌綸織物/PVC復(fù)合材料吸水性能及熱性能的影響,文章分別采用堿處理、堿溶液與上漿劑聯(lián)合處理的方法對(duì)滌綸織物進(jìn)行改性處理,利用接觸成型技術(shù)制備滌綸織物/PVC復(fù)合材料。采用掃描電鏡對(duì)滌綸織物/PVC復(fù)合材料的斷面形貌進(jìn)行觀察,對(duì)復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)和熱穩(wěn)定性進(jìn)行測(cè)試分析。研究發(fā)現(xiàn),織物改性處理降低了滌綸織物/PVC復(fù)合材料的吸水性能,隨著浸泡時(shí)間的延長(zhǎng),未改性處理、堿處理、堿溶液與上漿劑聯(lián)合處理滌綸織物/PVC復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)依次降低;改性處理對(duì)滌綸織物/PVC復(fù)合材料的熱穩(wěn)定性無(wú)顯著 影響。
關(guān)鍵詞: ?滌綸織物;改性處理;復(fù)合材料;吸水性能;熱性能
中圖分類號(hào): TS101.923;TQ342.2
文獻(xiàn)標(biāo)志碼: A
文章編號(hào): 1001 7003(2022)03 0028 05
引用頁(yè)碼: 031104
DOI: 10.3969/j.issn.1001-7003.2022.03.004 (篇序)
滌綸織物/聚氯乙烯(PVC)柔性復(fù)合材料具有質(zhì)量輕、強(qiáng)度高、可加工性能好等優(yōu)點(diǎn)? [1-3] ,廣泛應(yīng)用于體育建筑、商場(chǎng)、交通服務(wù)設(shè)施等大跨度建筑中。但由于滌綸織物/PVC柔性復(fù)合材料在實(shí)際應(yīng)用中存在易吸水和熱穩(wěn)定性差等缺點(diǎn),導(dǎo)致材料易發(fā)霉,抗疲勞性能差,從而影響其使用壽命,并在一定程度上限制其應(yīng)用。因此,研究滌綸織物/PVC柔性復(fù)合材料的吸水性能和熱性能十分有必要。
在包括滌綸織物/PVC復(fù)合材料在內(nèi)的層合復(fù)合材料的制備過(guò)程中,改善增強(qiáng)體與基體材料之間的界面結(jié)合是最關(guān)鍵的技術(shù)之一。目前最常用的方法是加入異氰酸酯類黏合劑以提高復(fù)合材料的界面黏結(jié)性能? [4-5] 。然而,異氰酸酯是極其有害的? [6] ,它不僅在生產(chǎn)過(guò)程中對(duì)工人的健康造成危害,還會(huì)在使用過(guò)程中釋放出甲醛等有害物質(zhì)。近年來(lái),對(duì)滌綸織物進(jìn)行表面改性,改善滌綸與基體材料之間的界面結(jié)合受到了眾多科研工作者的廣泛關(guān)注? [7-9] 。為此,本文采用堿處理、堿溶液與上漿劑聯(lián)合處理的方法對(duì)滌綸織物進(jìn)行改性處理,利用接觸成型技術(shù)制備滌綸織物/PVC復(fù)合材料,研究堿處理、堿溶液與上漿劑聯(lián)合處理對(duì)滌綸織物/PVC復(fù)合材料吸水性能及熱性能的影響。
1 實(shí) 驗(yàn)
1.1 材料及設(shè)備
平紋組織的滌綸織物,其經(jīng)、緯絲線規(guī)格均為55.56 tex/96 f,經(jīng)、緯向密度均為120根/10 cm(浙江金匯特材料有限公司),EPVC聚氯乙糊烯樹脂,牌號(hào)為P450,聚合度為1 000±150(上海氯堿化工股份有限公司),氫氧化鈉(分析純,杭州高晶精細(xì)化工有限公司),表面活性劑1227(工業(yè)級(jí),杭州科峰化工有限公司),抗靜電劑SN(工業(yè)級(jí),江蘇省安海石油化工廠), 檸檬酸三丁酯(TBC,98 % )、環(huán)氧大豆油(ESO,化學(xué)純)(阿拉丁試劑有限公司),SiO 2/TBC上漿劑(實(shí)驗(yàn)室自制)。
AL204分析天平(梅特勒托利多儀器(上海)有限公司),KQ-400KDE超聲波清洗器(昆山市超聲儀器有限公司),DHG-9146A鼓風(fēng)干燥箱(上海精宏實(shí)驗(yàn)設(shè)備有限公司),CH1015超級(jí)恒溫槽(上海衡平儀器儀表廠),JJ-6B數(shù)顯恒速電動(dòng)攪拌器(常州市金壇聯(lián)友儀器有限公司),ULTRA55型場(chǎng)發(fā)射電子顯微鏡(FE-SEM,德國(guó)ZEISS公司),Labsys Evo型熱重差熱分析儀(法國(guó)塞塔拉姆公司)。
1.2 方 法
1.2.1 滌綸織物的表面改性
滌綸織物表面處理的方法如表1所示。
1.2.2 滌綸織物/PVC復(fù)合材料的制備
采用接觸成型工藝制備滌綸織物/PVC復(fù)合材料。工藝流程如圖1所示,具體步驟為:
1) 先將EPVC、TBC和ESO按照質(zhì)量比100 ︰ 130 ︰ 7混合,以1 000 r/min的速度攪拌30 min,然后在真空干燥箱中進(jìn)行脫泡,制備均勻的樹脂糊混合物。
2) 分別將PF、PF-1、PF-2織物裁成20 cm×20 cm大小平放在聚四氟乙烯平板上,然后將制備的樹脂糊混合物澆注在滌綸織物上面,通過(guò)手動(dòng)輥緩慢地滾動(dòng)以確保滌綸織物完全被浸潤(rùn),并且擠出多余的樹脂糊。
3) 將復(fù)合材料置于165 ℃的烘箱中烘燥6 min,冷卻后反復(fù)進(jìn)行手糊工藝,保證所有復(fù)合材料試樣的厚度在0.85~0.88 mm。
1.3 測(cè)試與表征
1.3.1 復(fù)合材料斷面形貌觀察
利用ULTRA55型場(chǎng)發(fā)射電子顯微鏡(FE-SEM)對(duì)滌綸織物/PVC樹脂復(fù)合材料的斷面形貌進(jìn)行觀察,鍍金25 s,測(cè)試電壓10 kV。
1.3.2 吸水性能測(cè)試
按照GB/T 1034—2008《塑料吸水性的測(cè)定》(23 ℃水中吸水量的測(cè)定)方法。將復(fù)合材料試樣放入(50.0±2.0) ℃烘箱內(nèi)干燥至少24 h,然后在干燥器內(nèi)冷卻至室溫,稱量每個(gè)樣品,精確至0.1 mg。 然后將試樣放入盛有蒸餾水的容器中,水溫控制在(23.0±1.0) ℃。分別浸泡(24±1) h、(48±1) h、(72±1) h后,每隔48 h取出一次試樣,用清潔干布或?yàn)V紙迅速擦去試樣表面所有的水,再次稱量每個(gè)試樣,精確至0.1 mg。 試樣從水中取出后,在1 min內(nèi)完成稱量。
根據(jù)下式計(jì)算每個(gè)試樣相對(duì)于初始質(zhì)量的吸水質(zhì)量分?jǐn)?shù),實(shí)驗(yàn)結(jié)果以相同條件下得到的三個(gè)結(jié)果的算術(shù)平均值 表示。
c i/ % = m i-m 0 m 0 ×100? ?(1)
式中: c i 為試樣的吸水質(zhì)量分?jǐn)?shù), % ; m i 為浸泡后是試樣的質(zhì)量,mg; m 0 為浸泡前干燥后試樣的質(zhì)量,mg。
1.3.3 TG分析
熱失重(TG)分析是在程序升溫的環(huán)境中,測(cè)試試樣的質(zhì)量對(duì)溫度的依賴關(guān)系的一種技術(shù),用于分析復(fù)合材料的熱穩(wěn)定性。采用Labsys Evo型熱重差熱分析儀測(cè)試滌綸織物/PVC復(fù)合材料的熱穩(wěn)定性。測(cè)試前,需要把樣品切成均勻的小顆粒。設(shè)定測(cè)試溫度為室溫至750 ℃,升溫速率為10 ℃/min,在氮?dú)獗Wo(hù)下進(jìn)行測(cè)試。
2 結(jié)果與分析
2.1 復(fù)合材料斷面形貌
本文采用FE-SEM對(duì)滌綸織物/PVC樹脂復(fù)合材料斷裂面的形貌進(jìn)行觀察,結(jié)果如圖2所示。圖2(a)為PF織物/PVC復(fù)合材料的斷裂面,可以看出在復(fù)合材料斷裂過(guò)程中,織物被完全拔出基體,在基體表面留下清晰的凹痕,織物與基體產(chǎn)生明顯的脫黏現(xiàn)象,說(shuō)明織物與基體之間的結(jié)合不好。圖2(b)為PF-1織物/PVC復(fù)合材料的斷裂面,可以看到斷裂的織物殘留在基體中,在復(fù)合材料的斷裂面上織物與基體分離,這說(shuō)明經(jīng)過(guò)堿處理,織物表面粗糙度變大,增大了織物與基體的接觸面積,在一定程度上提高了復(fù)合材料的界面黏結(jié)強(qiáng)度。圖2(c)為PF-2織物/PVC復(fù)合材料的斷裂面,可以看出在復(fù)合材料的斷裂面,織物與基體的結(jié)合是令人滿意的。這是由于上漿處理改善了滌綸織物與PVC基體的浸潤(rùn)性,增大了基體浸潤(rùn)纖維的表面積,同時(shí)也增加了滌綸織物表面與PVC基體之間的相互作用點(diǎn),增強(qiáng)了滌綸織物與PVC基體之間的機(jī)械鎖合。上漿劑膜層類似于一個(gè)“橋梁”,牢固地連接著基體和織物? [10] 。因此,復(fù)合材料的界面黏結(jié)得到改善。
2.2 吸水性能
復(fù)合材料的吸水性不僅與復(fù)合材料中基體、增強(qiáng)體材料的吸水性有關(guān),還與復(fù)合材料的界面黏結(jié)情況密切相關(guān)。滌綸織物/PVC復(fù)合材料中,增強(qiáng)材料滌綸織物與基體材料PVC的吸水性能均很差,水分主要通過(guò)滌綸織物與PVC基體的界面孔隙的芯吸作用進(jìn)入到復(fù)合材料內(nèi)部。因此,復(fù)合材料的吸水率可以間接表征其界面黏結(jié)情況。
本文對(duì)相同規(guī)格的三種滌綸織物/PVC復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)進(jìn)行測(cè)試,結(jié)果如圖3所示。
從圖3可以看出,三種滌綸織物/PVC復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)均隨浸泡時(shí)間的延長(zhǎng)而升高,表明復(fù)合材料具有一定的吸濕能力。從整體來(lái)看,在浸泡初期,復(fù)合材料吸水的速率較快,隨著浸泡時(shí)間的延長(zhǎng),復(fù)合材料吸水的速率漸漸變慢。可以把復(fù)合材料的吸濕過(guò)程分為兩個(gè)階段: 第一階段的吸濕主要發(fā)生在復(fù)合材料的表面,水分沿著材料表面的微孔滲入到復(fù)合材料內(nèi)部;第二階段的吸濕主要發(fā)生在復(fù)合材料的界面,水分通過(guò)復(fù)合材料界面處的毛細(xì)作用進(jìn)入到復(fù)合材料的內(nèi)部? [11] 。由于三種滌綸織物/PVC復(fù)合材料試樣的表面結(jié)構(gòu)基本一樣,故在浸泡初期三種復(fù)合材料的吸濕規(guī)律大致相同。隨著浸泡時(shí)間的延長(zhǎng),復(fù)合材料的吸濕通過(guò)復(fù)合材料界面處的毛細(xì)作用,三種復(fù)合材料的吸濕規(guī)律出現(xiàn)了明顯的差異,這足以說(shuō)明三種復(fù)合材料的界面結(jié)構(gòu)差異較大。從圖3還可以看出,PF織物/PVC復(fù)合材料、PF-1織物/PVC復(fù)合材料、PF-2織物/PVC復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)依次降低,表明它們的界面結(jié)合依次緊密。這與上文復(fù)合材料斷裂面形貌照片的結(jié)果吻合。
2.3 熱穩(wěn)定性
熱失重法是測(cè)定聚合物熱穩(wěn)定性常用的方法之一,其除了可以用來(lái)分析材料的熱穩(wěn)定性和熱分解過(guò)程之外,還可以用來(lái)測(cè)定材料中的組分及水分揮發(fā)物等。本文采用Labsys Evo型熱重差熱分析儀測(cè)試滌綸織物/PVC復(fù)合材料的熱重曲線,結(jié)果如圖4所示。
從圖4可以看出,三種滌綸織物/PVC復(fù)合材料的TG曲線在25~200 ℃平穩(wěn)中略有降低,主要是由于復(fù)合材料中水分的揮發(fā)。TG曲線在200 ℃左右迅速下降,表明復(fù)合材料從200 ℃左右開始分解。在200~350 ℃分解速率最快,至 350 ℃時(shí) 失重約為70 % 多,趨于平穩(wěn);當(dāng)溫度升至420 ℃左右時(shí)又逐漸分解,直至500 ℃曲線平穩(wěn)。以上結(jié)果表明,織物改性處理對(duì)滌綸織物/PVC復(fù)合材料的熱穩(wěn)定性沒(méi)有顯著影響。
3 結(jié) 論
通過(guò)對(duì)滌綸織物進(jìn)行表面改性,利用接觸成型技術(shù)制備滌綸織物/PVC復(fù)合材料。先對(duì)滌綸織物/PVC復(fù)合材料的斷面形貌進(jìn)行觀察,后對(duì)復(fù)合材料的吸水性能和熱穩(wěn)定性進(jìn)行測(cè)試分析,得到如下結(jié)論:
1) 織物改性處理使滌綸織物/PVC復(fù)合材料的界面黏結(jié)得到改善。
2) 隨著浸泡時(shí)間的延長(zhǎng),未改性處理滌綸織物/PVC復(fù)合材料、堿處理滌綸織物/PVC復(fù)合材料、堿溶液與上漿劑聯(lián)合處理織物/PVC復(fù)合材料的吸水質(zhì)量分?jǐn)?shù)依次降低,表明織物改性處理降低了滌綸織物/PVC復(fù)合材料的吸水性能。
3) 三種滌綸織物/PVC復(fù)合材料的TG曲線的規(guī)律基本一致,表明織物改性處理對(duì)滌綸織物/PVC復(fù)合材料的熱穩(wěn)定性沒(méi)有顯著影響。
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Influences of fabric modification treatment on water absorption and thermal properties of polyester fabric/PVC composites
PU Dandan 1, ZHOU Han 1, PU Qing 2
(1.School of Textiles, Henan University of Engineering, Zhengzhou 450007, China; 2.Electrical Inspection Center, Henan Institute of Product Quality Supervision and Inspection, Zhengzhou 450004, China)
Abstract:
With the development of polyester industrial technology, the mechanical properties of polyester industrial yarn such as strength and modulus have been continuously improved. The application field of composites reinforced with polyester fiber (fabric) has also been expanding because of its advantages such as lightweight, flexibility and good weavability. Among them, polyester fiber (fabric) reinforced polyvinyl chloride (PVC) flexible composites have been widely used in long-span buildings such as sports buildings, shopping malls, transportation service facilities and so on due to the high strength and modulus, good dimensional stability, strong bearing capacity and excellent fatigue resistance. However, polyester, characterized by smooth surface, lack of polar groups and chemical inertia on the surface, is difficult to excellently bond with PVC matrix, resulting in poor interfacial bonding strength of PVC matrix composites. As a result, polyester fabric/PVC flexible composites have disadvantages such as high water absorption and poor thermal stability in practical application, resulting in proness to going mouldy and poor fatigue resistance of materials. This affects the service life and limits the application to a certain extent. Therefore, it is necessary to study the interface bonding properties of polyester fabric/PVC flexible composites under modified treatment and their relationship with water absorption and thermal properties.
In order to investigate the influence of fabric modification treatment on the water absorption and thermal properties of polyester fabric/PVC composites, the polyester fabric was modified by alkali treatment, alkali solution and sizing agent combined treatment, and the polyester fabric/PVC composites were prepared by contact molding technology. Scanning electron microscopy (SEM) was used to observe the section morphology of polyester fabric/PVC composites, and the water absorption fraction and thermal stability of the composites were tested and analyzed. Based on the above, this paper adopted the method of correspondence analysis to investigate the relationship between water absorption and interfacial bond of polyester fabric/PVC composites. It is found that with the increase in surface roughness of alkali treated polyester fabric, the contact area between fabric and matrix is increased, and the interfacial adhesion of composites is improved to a certain extent. Sizing treatment improves the wettability between polyester fabric and PVC matrix, increases the interaction point between polyester fabric surface and PVC matrix, and strengthenes the mechanical locking between polyester fabric and PVC matrix. Therefore, the interface bonding of the composites is improved. Fabric modification reduces the water absorption of polyester fabric/PVC composites, and with the extension of soaking time, the moisture absorption of composites is realized mainly through the capillary action at the interface of composites. There are obvious differences in the moisture absorption laws of unmodified polyester fabric/PVC composites, alkali treated polyester fabric/PVC composites, alkali solution and sizing agent jointly treated fabric/PVC composites, indicating a great difference in the interfacial structures of the three composites. The water absorption mass fraction of unmodified polyester fabric/PVC composites, alkali treated polyester fabric/PVC composites, alkali solution and sizing agent jointly treated fabric/PVC composites decrease successively, indicating their close interface bonding in sequence. Fabric modification has no significant effect on the thermal stability of polyester fabric/PVC composites.
The relationship between water absorption and interfacial bond of polyester fabric/PVC composites can bring inspiration for characterization of structural composites. The worse the water absorption property of structural composite, the better the interface bonding property. The results of this research can provide reference for the characterization of structural composites in the future.
Key words:
polyester fabric; modification treatment; composites; water absorption property; thermal property