【正文】 單鍵內(nèi)旋轉(zhuǎn)的難易 分子結(jié)構(gòu) 主鏈結(jié)構(gòu) 取代基結(jié)構(gòu) 分子鏈長(zhǎng)度 《 1》主鏈結(jié)構(gòu) structure of main chain ? 主鏈具有 CO、 CN和 SiO結(jié)構(gòu) —— 柔順性好 ? Main chain has structure as CO, CN and SiO facility increasing 原因：鄰近的非鍵合原子或基團(tuán)少 ,空間阻礙小，內(nèi)旋轉(zhuǎn)位壘小 Cause : adjacent nonbonded atom or group decreases。 space baffle and inner eddy potential energy decreases 《 1》主鏈結(jié)構(gòu) main chain ? 主鏈單鍵的鍵長(zhǎng)鍵角大 —— 柔順性好 The bond length and angle increases results in facility increasing 原因：空間位阻小，內(nèi)旋轉(zhuǎn)阻礙小 cause: space and inner eddy baffle decreasing 《 1》主鏈結(jié)構(gòu) main chain ? 主鏈含有苯環(huán)（或其它環(huán)狀結(jié)構(gòu)） —— 柔順性差 main has ringy structure as benzene ? facility decreasing 原因：大 π平面結(jié)構(gòu)不能內(nèi)旋 , 非大 π平面結(jié)構(gòu)的酯環(huán)結(jié)構(gòu)中單鍵內(nèi)旋轉(zhuǎn)也極難 Cause: π planar structure results in that the inner eddy of macromolecules difficult and ringy ester are difficult, too. ? 主鏈含有孤立雙鍵 —— 柔順性好 The main has island double bond facility increasing 原因：鄰近單鍵的非鍵合原子間距增大 , 空間位阻小，內(nèi)旋轉(zhuǎn)位壘小 Cause: space between nonbonded atom of contiguity single bond increases。 space and inner eddy baffle decreases 《 2》取代基結(jié)構(gòu) The structure of substitutional group ? 取代基 (非極性）體積大 —— 柔順性差 PSPP ? The volume of substitutional group (nonpolarity) is greatfacility decreasing PSPP 原因：空間位阻大，內(nèi)旋轉(zhuǎn)阻礙大，位壘高 Cause: space and inner eddy baffle and potential energy difference aregreat ? 取代基極性大 —— 柔順性差 PE PECl PVC ? The polarity of substitutional group is strong facility decreasing PE PECl PVC ? 取代基數(shù)量多 —— 柔順性差 ? The amount of substitutional group is excessive facility decreasing ? 取代基對(duì)稱結(jié)構(gòu) —— 柔順性好 the substitutional group is symmetry facility increasing 原因：對(duì)稱取代使極性抵消，減小分子間相互作用 , 使內(nèi)旋轉(zhuǎn)容易 Cause: The polarity of symmetry substitutional group is counteracted and the inner eddy bee to easy by molecular reciprocity decreasing. C H 2* C *C H 3 nC H 3C H 2* HC *C H 3 n C H 2*HC *n C H 2*HC *C H 3 n 《 3》分子鏈長(zhǎng)度 The length of chain 分子量大、分子鏈長(zhǎng) —— 柔順性好 Molecular weight or length of chain increasesfacility increasing 當(dāng) M 104 時(shí)影響不明顯 The effect is not prominence when M 104 原因？ Cause ? 《 4》分子內(nèi)或分子間作用力 The interaction of molecular inner or between macromolecules NCCNNCHHHOOONCCNNCHHHOOONCCNNCHHHOOOCNCNCNHHHOOON y l o n 6 6a b由于形成了分子間氫鍵，阻礙了分子鏈內(nèi)旋轉(zhuǎn)，從而使聚合物的剛性增大 The rigidity of polymer increases because it formed the hydrogen bond and hindered molecular inner eddy. 分子結(jié)構(gòu)對(duì)柔順性的影響總結(jié) The summary about the effect of molecular structure on facility of chain ? 主鏈結(jié)構(gòu)： 醚鍵 柔順性 ? Main chain: aether bond facility 孤立雙鍵 柔順性 island double bond facility 鍵長(zhǎng)、鍵角大 柔順性 bond length and angle facility 苯環(huán)、環(huán)狀結(jié)構(gòu) 柔順性 ringy molecular structure facility ? 取代基結(jié)構(gòu) : 體積大 柔順性 ? The structure of substitutional group: volume increasing facility 極性大 柔順性 polarity increasing facility 數(shù)量多 柔順性 The amount is excessive facility 對(duì)稱取代 柔順性 the substitutional group is symmetry facility ? 分子鏈長(zhǎng)度：分子量超過一定值后影響不明顯