增长:
RCH2CHCl.+VcRCH2CHCH2CHClCl.......R(CH2CH)nClCH2CHCl.
终止: 歧化:
歧化
R(CH2 CH)nCH2CH+R(CH2 CH)mCH2CH
ClClCl Cl
偶合: R(CH 2 CH)nCH2CH+R(CH2 CH)mCH2CH
ClClClCl
..R(CH2 CH)nCH2 CH2ClCl+R(CH2 CH)mCH CHClCl..偶合R(CH2 CH)nClCH2 CHClCHCH2(CHCH2)mRClCl
6.解:引发剂分解为一级反应
[I]od[I]??kdt??kdtln[I]d[t]
以
[I]oln=kdt[I]kd2 = = = 1.09 (h)
∽ t 作图,直线斜率即为 kd=1.76?10(S)
-4
-1
t
1ln2kd0.69321.76×104×3600
7.
8.解:log t1 =
22A?B Tt1 = 10 h ,T = 273 + 45 =318 (k) t1 = 1 h ,T = 273 + 61 =334 (k)
2lg 10 =
A - B = 1 318
lg 1 =
A334 - B = 0 A = 6638 , B = 19.88 ∵ tln21 =
, t2k1 = 10, 1 时, lg t1 =1,0
d22∴ 很以求得 、
kEd 及 Ad 值
d1lg kd= lg Ad - 2.303RTEd
kdElg t
12 = lg(ln2) – ln
d2.303RT= lg(ln2) – lg Ad +
EdAd= 2.303RT - lg ln2
A=
EB = lg = lg dAdAd9.
2.303RTln20.693解: -d[I]/dt=k1[I]+k3[S·][I] (1)
d[R·]/dt=0 2kk2
1[I]+k3[S·][I]–2[R·][HS]–2k4[R·]=0 (2)
d[S·]/dt=0 k2[R·][HS]-k3[S·][I]=0 (3)
∴ k2[R·][HS]=k3[S·][I] (4) ∴ [S·]=k2[HS][R·]/(k3[I]) (5) (4)代入(2)得:2k1[I]=2k4[R·]2
∴ [R·]=(k1/2
1[I]/k4) (6) -d[I]/dt = k1[I] + k3[S·][I]
= k1[I] + k3[I](k2[R·][HS]/k3[I])
= k1/2
1[I] + k3[I](k2[HS]/k3[I])(k1[I]/k4)
= k1/21/2
1[I] + k2(k1/k4)[HS][I] 另: -d[I]/dt = k1[I] + k3[S·][I] = k1[I] + k2[R·][HS]
= k[I]/k1/2
1[I] + k2[HS]·(k14)
= k1/21/2
1[I] + k2(k1/k4)[HS][I]
10.
解: Rp ∝ [I] 双基终止机理得到
1
Rp ∝ [I] 单基终止机理得到
0
Rp ∝ [I] 活性链浓度与引发剂浓度无关,如光、热引发聚合
0.5-1
Rp ∝ [I] 单、双基终止同时存在
0-0.50
Rp ∝ [I] 介于双基终止于Rp ∝ [I]之间 单基终止时: Rt = kt[M·]
稳态处理:Ri = 2fkd[I] = kt[M·] [M·] = 2fkd[I]/kt
Rp = kp[M·][M] = 2fkpkdf[I][M]/kt 11.
1/23
解:(1) 设 X = [I][M]χ10
则相应的X为139,115,87.6,65.5,50.8,30.0 以X为横坐标,以Rp为纵坐标作图,得直线即证
2-2
(2) kp/kt = 3.37χ10
1/2
K = kp(fkd/kt)
取两点 纵:1.84,0.415 ; 横:130.0,30.0
-4-3-3
K = (1.84-0.415)χ10/(130-30)χ10 = 1.42χ10
2-32-2
kp/kt = k2/fkd = (1.42χ10)/fkd = 3.37χ10 R = 1.987 12.
解:(1) 苯乙烯分子量为 104 ,密度为0.887 [ M ]= 887/104 = 8.53 mol/l BPO 分子量= 242
[ I ] =(887×0.109 %)/242 = 3.96×10-3 (2) 苯乙烯偶合终止, = 2XnυRp Rpυ = = 1230 = = XnRiRt 2Ri = Rp/υ = 2.07×10-8 mol/l·s = Rt ( 3 )
kd = Ri/2f[I] = 3.27×10-6 S-1 kt = Rt/2[M·]2 = 3.58×107 mol/l·s
kp = Rp/[M][M·]=0.255×10-4/8.53×1.70×10-8=176 -8 -6Rk[ M ] 8.53 i 10d 10
-3Kp 102 [M?¤] 1.70?á10-8 Rp 10 -8 Rt 10 Kt 107 可知: kt >> kp 但[ M ] >> [M·], 因此: Rp >> Rt
所以可得到 很大的聚合物。 Xn
1/2
13. 14.
解: Xn= 1.30ν X + Y = 1
ν 1.30 ν = X
+Y ∴ X = 0.426, Y = 0.538 2 15.
解: (1) 以1/Xn — [S]/[M] 作图(3—56)
-4-4-5
由图得斜率 Cs = (9.6χ10-5.7χ10)/(11.0-4.5) =6.0χ10
-4
截距(1/Xn)0 = 2.8χ10
(2)1/Xn = (1/Xn)0 + Cs[S]/[M]
甲苯与苯乙烯摩尔比 [S]/[M] = (1/Xn-1/(Xn)0)/Cs
-4-4
Xn = 1500, 1/Xn = 6.7χ10, 由上图截距(1/Xn)0 = 2.8χ10
-4-4-5
∴ [S]/[M] = (6.7χ10-2.8χ10)/6.0χ10 = 6.5 16.
解: Xn = 2ν = 2Rp/Ri ∴ (1/Xn)0 = Ri/2Rp
∴ 1/Xn = Ri/2Rp + Cs[s]/[M]
[苯乙烯S]:M=104, 1mol苯乙烯所占体积=104/887=0.117(l) 苯所占体积=1-0.117=0.883(l)
[苯M] = 839χ0.883/78 = 9.5(mol/l)
-4
Xn = 5000, 1/Xn = 2.0χ10 Cs = (1/Xn-Ri/2Rp)/([S]/[M])
-4-11-7
= (2.0χ10-4.0χ10/(2χ1.5χ10))/9.5
-6
= 7.05χ10 17. 解:
1. 由于氯乙烯的CM特别大,以致于Rt远小 于RtrM(P75), 因此: RpRp1Xn=≈= Rt+RtrMRtrMCMCM仅与温度T有关, 因此聚合度可由温度调节,而与引发剂浓度无关, 随T的升高,聚合度降低。 18. 19. 解:
(1) 50℃~60℃时速率常数变化
11 ER=EP+EdEt2211
=32.6+×125.6×10 22 = 90.4
T1 = 273 + 50 = 323 K T2 = 273 + 60 = 333 K
K290.411=exp×()=2.96
K18.3×10332333380℃~90℃时速率常数变化
K2=2.34
K1 (2) 50℃~60℃时 Xn变化
11
EXn=EPEtE 22d11
=32.6×125.6×10 22= - 35.2 KJ/mol
Xn2K2'35.211
='=exp×()=0.6758.3×103323333 Xn1K180℃~90℃时 变化 Xn
Xn2K2'35.211
='=exp×()=0.7198.3×103353363 Xn1K1(3). 光引发时50℃~60℃时速率常数及 变化 Xn
Ed=011
E=EPEt=32.6×10 22 ER=EXn50℃~60℃时 Xn2RP2E11==exp×()=1.39
RRTTXn1P11280℃~90℃时 Xn2RP2E11==exp×()=1.30 RRTTXn1P112 20.
解: ΔG = ΔH – TΔS
聚合时,熵减小,所以ΔS为负值,约为-105— -125J/mol.K, T一般在室温~100℃ 则-TΔS约为30—42 KJ/mol 聚合反应一般为放热反应,ΔH< 0
理论计算:(P125页) |ΔH| = 90 KJ/mol ∴ |ΔH|> T|ΔS|