5．解：

（1）

(CH3)2CN

CN

NC(CH3)2

引发：

CN

N2 + 2(CH2)C (R )

..

C

R

.+

CH3

CH2

CCH3COOCH

3

R

CH2

.

3

COOCH

增长：

CH3

R

CH2C

.

CH3

+

CH2

3)COOCH3

RCH2

CH2

CH3C

.

CH3

COOCH3

COOCH3COOCH3

……

CH3

R(CH2

C

CH2

3

n-1

.

COOCHCOOCH3

终止：

CH3

R

CH2

C

CH2

CH3CH3

+R

CH2

C

CH2

CH3..

COOCH3COOCH3COOCH3COOCH3

CH3

R

CH2

CH2

CH3H

+

R

CH2

CH3mCH2

2COOCH3

COOCH3COOCH3COOCH3

CH3

R

CH2

C

nCH2

CH3COOCH3

CH3CH2

CH3C

CH2)mR

COOCH3COOCH3COOCH3