Slide cao su hóa học và công nghệ chemistry of accelerated sulfur vulcanization

.c
om

cu

u

du
o

ng

th

an

co

ng

CHEMISTRY OF
ACCELERATED SULFUR
VULCANIZATION

CuuDuongThanCong.com

/>

du
o

ng

th

an

co

ng

Benzothiazole group
2- Mercaptobenzothiazole
2-bisbenzothiazole-2,2’-disulfide
2-bisbenzothiazole-2,2’-polysulfide
Zinc-mercaptobenzothiazole polysufides
Rubber
Benzothiazole terninated polysulfidic radilcal
2-cyclohexyldithiobenzothiazole

u

Bt
MBT or BtSH
MBTS or Br-SS-Bt
BTP or BtS-SX-SBt
BtS-Zn-SX-SBt
RH
Bt-SX*
CDB

cu

•
•
•
•
•
•
•
•

.c
om

List of Abbreviations

CuuDuongThanCong.com

/>

.c
om
an

co

ng

• A- ACCELERATED CHEMISTRY
• B. CROSSLINKING CHEMISTRY

cu

u

du
o

ng

th

• C. POST-CROSSLINKING CHEMISTRY

CuuDuongThanCong.com

/>

.c
om

A- ACCELERATED CHEMISTRY

co

ng

• Formation of MBTS from MBS
• Reaction of sulfur with MBTS and other

cu

u

du
o

ng

th

an

accelerator polysulfides
• Exchange reaction among acceleratorpolysulfides
• Effect of ZnO-Formation of ZincAccelerator Complexes

CuuDuongThanCong.com

/>

.c
om

B. CROSSLINKING CHEMISTRY

co

ng

• Formation of crosslink precursors
• Conversion of crosslink precursors to

cu

u

du
o

ng

th

an

crosslink
• Scorch delay reaction

CuuDuongThanCong.com

/>

.c
om

C. POST-CROSSLINKING CHEMISTRY

co

ng

• Crosslink desulfuration
• Crosslink degradation and main- chain-

cu

u

du
o

ng

th

an

modification

CuuDuongThanCong.com

/>

.c
om
ng
co
an
th

ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om
ng
co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om
ng
co
an
th

ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om
ng
co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om

• (a) sulfur crosslinks (y=1 mono, y=2 di,

cu

u

du
o

ng

th

an

co

ng

y>2 polysulfide crosslinks
• (b) carbon-carbon crosslink
ã â Pendant accelereator sulfide where X is
the accelerator moiety
• (d) Cyclic sulfide
• (e) Vicinal crosslinks

CuuDuongThanCong.com

/>

.c
om
ng

co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om
ng

cu

u

du
o

ng

th

an

co

A- ACCELERATOR CHEMISTRY

CuuDuongThanCong.com

/>

cu

u

du
o

ng

th

an

co

ng

.c
om

Formation of MBTS from MBS

CuuDuongThanCong.com

/>

.c
om

Reaction of sulfur with MBTS and
other Accelerator-polysulfides

cu

u

du
o

ng

th

an

co

ng

A key intermediate that reacts with
elemental sulfur is MBTS

CuuDuongThanCong.com

/>

.c
om
ng
co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

.c
om
ng
co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

cu

u

du
o

ng

th

an

co

ng

.c
om

Exchange reaction among
accelerator polysulfide

CuuDuongThanCong.com

/>

cu

u

du
o

ng

th

an

co

ng

.c
om

Effect of ZnO-Formation of ZincAccelerator Complexes

CuuDuongThanCong.com

/>

co

ng

.c
om

Zinc-accelerator complexes may also
undergo exchange reactions with other zincaccelerator complexes to yield a distribution
of Zn-accelerator species

du
o

ng

th

an

Bt-Zn-SX-Bt + Bt-Zn-SY-Bt

cu

u

Bt-SZ-Zn-Bt + Bt-SX+Y-Z-Zn-Bt

CuuDuongThanCong.com

/>

.c
om

ng

cu

u

du
o

ng

th

an

co

B- Crosslink chemistry

CuuDuongThanCong.com

/>

.c
om

Formation of crosslink precursors
• Crosslink precursors are formed when the

cu

u

du
o

ng

th

an

co

ng

accelerator polysulfides react with the
rubber chains, resulting in structures
RSX-SBt
• If Zinc is complexed to the accelerator
polysulfide, the crosslink precursors can
be BtS-Zn-SXSBt

CuuDuongThanCong.com

/>

.c
om

Conversion of crosslink precursors
to crosslinks
RSY* + BtSZ*

co

ng

RSXSBt

RSYR

ng

th

an

RSY* + Rubber

cu

u

du
o

BtSZ* can undergo a variety of reaction like
radical recombination to yield BtSSXSBt

CuuDuongThanCong.com

/>

.c
om
ng
co
an
th
ng
du
o
u
cu
CuuDuongThanCong.com

/>

cu

u

du
o

ng

th

an

co

ng

.c
om

The Zinc chelation can stabilize other sulfur bonds.
Thus, in the presence of Zinc many of S-S bonds
can break

CuuDuongThanCong.com

/>