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聚氨酯密封膠的粘性與彈性模量成反比
- 發(fā)布時(shí)間 : 2023-3-7 17:05:59
- Views:
(Summary description)Customized SILICONE STRUCTURAL SEALANT from China manufacturer refers to the adhesive with high strength, can bear large load, aging resistance, fatigue resistance and corrosion resistance, and has stable performance within the expected life. It is suitable for bearing the bonding of strong structural parts. Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for structural adhesive bonding. NEUTRAL SILICONE WETHERPROOF SEALANT from China manufacturer is a structural adhesive with waterproof function. Silicone glue refers to the adhesive based on silicone rubber. According to different functions, it can be divided into structural adhesive, potting adhesive, sealant, thermal conductive adhesive, flame retardant adhesive and so on.
聚氨酯密封膠的粘性與彈性模量成反比
(Summary description)Customized SILICONE STRUCTURAL SEALANT from China manufacturer refers to the adhesive with high strength, can bear large load, aging resistance, fatigue resistance and corrosion resistance, and has stable performance within the expected life. It is suitable for bearing the bonding of strong structural parts. Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for structural adhesive bonding. NEUTRAL SILICONE WETHERPROOF SEALANT from China manufacturer is a structural adhesive with waterproof function. Silicone glue refers to the adhesive based on silicone rubber. According to different functions, it can be divided into structural adhesive, potting adhesive, sealant, thermal conductive adhesive, flame retardant adhesive and so on.
- 發(fā)布時(shí)間 : 2023-3-7 17:05:59
- Views:
本文所研制的自修復(fù)輪胎聚氨酯密封膠以鹵化丁基橡膠或丁基橡膠與中分子量聚異丁烯為基體材料,中低分子量PIB和少量低分子量的樹脂為增粘劑和粘度調(diào)節(jié)劑,配合硫化劑和少量填料及防老劑等共混制得。該聚氨酯密封膠可通過擠出涂敷在輪胎內(nèi)側(cè),通過烘烤熱處理在輪胎內(nèi)側(cè)形成微交聯(lián)結(jié)構(gòu)并定型,也可以配合背紙制成卷材直接貼到輪胎內(nèi)側(cè)。此氣密膠的粘性主要來自于低分子量的聚異丁烯(PIB2300 ),分子量較低的聚異丁烯分子活動(dòng)性要遠(yuǎn)強(qiáng)于丁基橡膠,使膠料與輪胎內(nèi)面膠的接觸面上更容易產(chǎn)生吸附和纏結(jié)。在輪胎的運(yùn)行過程中,若有異物刺破輪胎,氣密膠會(huì)在回彈性和自身粘性的作用下粘在異物表面,與異物粘合在一起,將縫隙堵死,并適量浸入輪胎破孔與異物之間;當(dāng)異物脫出后,聚氨酯密封膠會(huì)靠自身回彈性和粘性自行愈合,輪胎破孔內(nèi)側(cè)會(huì)有自修復(fù)聚氨酯密封膠適量浸入并以自身粘性粘住破孔,由于膠料存在微交聯(lián)結(jié)構(gòu),雖然模量很低,但仍具有較強(qiáng)回彈性和本體強(qiáng)度,因此不會(huì)持續(xù)流出破孔,只會(huì)在破孔內(nèi)側(cè)一端適量浸入,使車胎被刺扎后可持續(xù)保持胎壓。
自修復(fù)充氣輪胎的聚氨酯密封膠可通過自身恰當(dāng)?shù)牧髯冃院妥哉承栽谔鹤饔孟伦孕蟹舛虏⒄匙÷馄瓶�,使輪胎破孔自行粘合。由于粘合過程不發(fā)生化學(xué)反應(yīng),僅在胎壓的壓力和膠料自身的回彈性作用下即可完成,因此自修復(fù)充氣輪胎氣密膠可以視為一種聚氨酯密封膠。聚氨酯密封膠粘劑是一種粘彈性材料,能夠與被粘物在短接觸時(shí)間內(nèi)施加輕接觸壓力時(shí),強(qiáng)烈地附著在表面,目前聚氨酯密封膠己被廣泛用于、、標(biāo)簽制品等產(chǎn)業(yè);聚氨酯密封膠的性能特點(diǎn),如用品上的給性和皮膚友好性,主要取決于膠料性能的平衡(耐刺扎、耐剝離和抗剪切)、釋放力和粘聚強(qiáng)度以及粘劑配方:這些屬性之間的平衡必須根據(jù)聚氨酯密封膠的具體最終用途而改變。壓膠必須能夠在廣泛的溫度、濕度和應(yīng)用頻率條件下有效地執(zhí)行其功能�;w膠料的粘彈性性能、自身型狀以及增粘劑的表面能會(huì)影響聚氨酯密封膠的性能X55]。大多數(shù)聚氨酯密封膠是許多成分的混合物,包括彈性體、攔截劑、增塑劑和填物。由于這些材料的復(fù)雜性,通常很難量化單個(gè)變量,例如分子量,對(duì)粘合劑性能的影響。
聚氨酯密封膠的粘性與彈性模量成反比,它的粘性應(yīng)該足夠高,以使膠料表面通過僅僅接觸和按壓到基底來實(shí)現(xiàn)粘合,根據(jù)達(dá)爾奎斯特準(zhǔn)則,一般聚氨酯密封膠的模量低于自修復(fù)輪胎聚氨酯密封膠亦復(fù)如是,需要在回彈后一以胎壓的作用下即可自行愈合粘住破洞保持胎壓。聚氨酯密封膠的剝離強(qiáng)度的D.H.Kaeble表達(dá)式一般可簡化為為:式3-1中,P為剝離力,b為測試區(qū)寬度,a為膠層厚度,6F為界面拉伸破壞極限力e為剝離角度。此式表明,剝離強(qiáng)度P/b除了跟膠層厚度有關(guān),還與模量成反比,所以,在不發(fā)生內(nèi)聚破壞的前提下,模量越低則粘性越好。本文中表征粘性的方式主要是初粘性、持粘性以及T型剝離強(qiáng)度。T型剝離強(qiáng)度按照國標(biāo)GB/T 2791-I 995測試,被粘物為玻璃紙,此測試方法主要針對(duì)較軟較薄被粘物。聚氨酯密封膠粘性與粘度成負(fù)相關(guān),一般本體粘度大于l OBPa-s的都不能作為聚氨酯密封膠。之所以粘性與粘度負(fù)相關(guān),可用麥克斯韋粘彈性材料模型來解釋。為型變量t為時(shí)間G為麥克斯韋模型中彈簧的楊氏模量l為牛頓勃壺粘度,由于輪胎胎壓施力是持續(xù)的緩慢的,故這一等式右邊第一項(xiàng)可忽略不計(jì),由于自修復(fù)聚氨酯密封膠是封存在輪胎內(nèi)面膠內(nèi)側(cè),是長時(shí)間受壓,主要表現(xiàn)出的就是流動(dòng)性。此輪胎發(fā)生破損后自我粘結(jié)封堵速率主要由第二項(xiàng)來決定,這也揭示了粘度越小,膠料的表面粘性越好的原因。由此也可粗略推演,在不發(fā)生內(nèi)聚破壞的前提下,膠料粘度n越小。m.hbxqtax.com
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