| 3 | 1/1 | 返回列表 |
| 查看: 573 | 回復(fù): 2 | |||
haizhoubuer新蟲(chóng) (初入文壇)
|
[求助]
親們,江湖告急,求翻譯。
|
Fig. 1(b) shows that the reaction time greatly influences the water absorbency of the resin, which increases with time. When the reaction time was 4 h, the resin water absorbency in distilled water was 1083.9 g/g, and 95.62 g/g in 0.9 wt.% NaCl. At a reaction time of 5 h, the resin water absorbency decreased. These observations are in line with the free radical reaction rule, which states that if the reaction time is too short, polymerization does not proceed to completion and results in low relative molecular mass and small network size after swelling with low resin water absorbency. Therefore, the prolonged reaction time can increase the degree of polymerization at the beginning of the reaction. Steady-state polymerization was reached after 4 h of reaction. In this stage, the generation rate of the free radical is equal to its consumption rate, which establishes a dynamic equilibrium wherein the reaction time has no influence on water absorbency. On the other hand, a very long reaction time causes the degradation of resin and results in a low molecular weight (Xu, Li, & Sun, 2010). In addition, stirring causes shear stress in the reaction system for a long time, thereby decreasing its viscosity. The decrease in viscosity is not conducive to polymerization, therefore, decreases the water absorbency.![]() |
至尊木蟲(chóng) (知名作家)
Translator and Proofreader
| 圖1(b)表明,反應(yīng)時(shí)間極大地影響著樹(shù)脂的吸水率,其隨時(shí)間而增加。當(dāng)反應(yīng)時(shí)間為4小時(shí)時(shí),樹(shù)脂在蒸餾水中的吸水率是1083.9克/g,在0.9%的NaCl(重量百分比)中則為95.62克/克。當(dāng)反應(yīng)時(shí)間為5小時(shí)時(shí),樹(shù)脂的吸水率降低。這些觀察結(jié)果與自由基反應(yīng)的規(guī)則相符,該規(guī)則規(guī)定,如果反應(yīng)時(shí)間過(guò)短,聚合會(huì)不完全,導(dǎo)致形成一些分子質(zhì)量相對(duì)低的產(chǎn)物,溶脹后網(wǎng)絡(luò)的大小小,樹(shù)脂的吸水率低。因此,延長(zhǎng)反應(yīng)時(shí)間在反應(yīng)的開(kāi)始就可以提高聚合度。反應(yīng)4小時(shí)后達(dá)到穩(wěn)態(tài)聚合。在穩(wěn)態(tài)聚合階段,自由基的生成速率和其消耗速率是相等的,建立了一個(gè)動(dòng)態(tài)平衡,所以此時(shí)反應(yīng)時(shí)間對(duì)吸水率沒(méi)有影響。在另一方面,過(guò)長(zhǎng)的反應(yīng)時(shí)間會(huì)引起樹(shù)脂的降解并產(chǎn)生低分子量產(chǎn)物((Xu, Li, & Sun, 2010)。另外,攪拌在反應(yīng)體系中引起剪切應(yīng)力,長(zhǎng)時(shí)間后可降低其粘度。粘度降低不利于聚合反應(yīng),因此降低了吸水性。 |
新蟲(chóng) (初入文壇)
| 3 | 1/1 | 返回列表 |
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 求調(diào)劑院校信息 +4 | CX 330 2026-03-21 | 4/200 |
|
|---|---|---|---|---|
|
[考研] 考研調(diào)劑 +3 | 呼呼?~+123456 2026-03-21 | 3/150 |
|
|
[考研] 333求調(diào)劑 +5 | 87639 2026-03-21 | 7/350 |
|
|
[考研] 一志愿南大,0703化學(xué),分?jǐn)?shù)336,求調(diào)劑 +3 | 收到VS 2026-03-21 | 3/150 |
|
|
[考研] 工科0856求調(diào)劑 +3 | 沐析汀汀 2026-03-21 | 3/150 |
|
|
[考研] 317求調(diào)劑 +9 | 申子申申 2026-03-19 | 15/750 |
|
|
[考研] 一志愿山大07化學(xué) 332分 四六級(jí)已過(guò) 本科山東雙非 求調(diào)劑! +3 | 不想理你 2026-03-16 | 3/150 |
|
|
[考研] 一志愿華中科技大學(xué),080502,354分求調(diào)劑 +5 | 守候夕陽(yáng)CF 2026-03-18 | 5/250 |
|
|
[考研] 085600材料與化工 +8 | 安全上岸! 2026-03-16 | 8/400 |
|
|
[考研] 一志愿蘇州大學(xué)材料求調(diào)劑,總分315(英一) +5 | sbdksD 2026-03-19 | 5/250 |
|
|
[考研] 材料學(xué)求調(diào)劑 +4 | Stella_Yao 2026-03-20 | 4/200 |
|
|
[考研] 求調(diào)劑 +3 | eation27 2026-03-20 | 3/150 |
|
|
[考研] 求調(diào)劑 +3 | 暗涌afhb 2026-03-16 | 3/150 |
|
|
[考研] 081700化工學(xué)碩調(diào)劑 +3 | 【1】 2026-03-16 | 3/150 |
|
|
[考研] 材料工程專(zhuān)碩調(diào)劑 +5 | 204818@lcx 2026-03-17 | 6/300 |
|
|
[考研] 0703化學(xué)調(diào)劑 +3 | 妮妮ninicgb 2026-03-17 | 3/150 |
|
|
[考研] 材料,紡織,生物(0856、0710),化學(xué)招生啦 +3 | Eember. 2026-03-17 | 9/450 |
|
|
[考研] 308求調(diào)劑 +4 | 是Lupa啊 2026-03-16 | 4/200 |
|
|
[考研] 東南大學(xué)364求調(diào)劑 +5 | JasonYuiui 2026-03-15 | 5/250 |
|
|
[考研] 333求調(diào)劑 +3 | 文思客 2026-03-16 | 7/350 |
|