Unit 1 What are polymers?
What
are
polymers?
For
one
thing,
they
are
complex
and
giant
molecules
and
are
different from low molecular weight compounds like, say, common salt.
浠�涔堟槸楂樿仛鐗╋紵棣栧厛锛屼粬浠槸鍚堟垚鐗╁拰澶у垎瀛愶紝鑰屼笖涓嶅悓浜庝綆鍒嗗瓙鍖栧悎鐗╋紝璀璇?/p>
鏅�氱殑鐩愩�?/p>
To
contrast the
difference,
the
molecular
weight
of
common
salt
is
only
58.5,
while
that of a polymer can be as high as several hundred thousand, even more than thousand
thousands.
涓庝綆鍒嗗瓙鍖栧悎鐗╀笉鍚岀殑鏄紝鏅�氱洂鐨勫垎瀛愰噺浠呬粎鏄?/p>
58.5
锛岃�岄珮鑱氱墿鐨勫垎瀛愰噺楂樹簬
105
锛岀敋鑷冲ぇ浜?/p>
106
銆?/p>
These
big
molecules
or
鈥榤acro
-
molecules鈥?nbsp;
are
made
up
of
much
sma
ller
molecules,
can be of one or more chemical compounds.
杩欎簺澶у垎瀛愭垨鈥滈珮鍒嗗瓙鈥濈敱璁稿灏忓垎瀛愮粍鎴愩�傚皬鍒嗗瓙鐩镐簰缁撳悎褰㈡垚澶у垎瀛愶紝澶у垎瀛?/p>
鑳藉鏄竴绉嶆垨澶氱鍖栧悎鐗┿�?/p>
To illustrate, imagine that a set of rings has the same size and is made of the same
material.
When
these
things
are
interlinked,
the
chain
formed
can
be
considered
as
representing a polymer from molecules of the same compound.
涓句緥璇存槑锛屾兂璞′竴缁勫ぇ灏忕浉鍚屽苟鐢辩浉鍚岀殑鏉愭枡鍒舵垚鐨勭幆銆傚綋杩欎簺鐜浉浜掕繛鎺ヨ捣鏉ワ紝
鍙互鎶婂舰鎴愮殑閾剧湅鎴愭槸鍏锋湁鍚岀鍖栧悎鐗╃粍鎴愮殑楂樿仛鐗┿�?/p>
Alternatively, individual rings could be of different sizes and materials, and interlinked
to represent a polymer from molecules of different compounds.
鍙︿竴鏂归潰锛岀幆鍙互澶у皬涓嶅悓銆佹潗鏂欎笉鍚?/p>
,
鐩歌繛鎺ュ悗褰㈡垚鍏锋湁涓嶅悓鍖栧悎鐗╃粍鎴愮殑鑱氬悎
鐗┿�?/p>
This interlinking of many units has given the polymer its name, poly meaning 鈥榤any鈥?nbsp;
and mer meaning 鈥榩art鈥?nbsp;(in Greek).
鑱氬悎鐗╃殑鍚嶇О鏉ヨ嚜浜庤澶氬崟鍏冪浉杩炴帴锛?/p>
poly
鎰忓懗鐫�鈥滃銆佽仛銆侀噸澶嶁�?/p>
锛?/p>
mer
鎰忓懗鐫�
鈥滈摼鑺傘�佸熀浣撯�?/p>
锛堝笇鑵婅涓級
銆?/p>
As an example, a gaseous compound called butadiene, with a molecular weight of 54,
combines
nearly
4000
times
and
gives
a
polymer
known
as
polybutadiene
(a
synthetic
rubber) with about 200 000molecular weight.
渚嬪锛?/p>
姘旀�佸寲鍚堢墿涓佷簩鐑殑鍒嗗瓙閲忎负
54
锛?/p>
杩炴帴
4000
娆″彲寰楀埌鍒嗗瓙閲忓ぇ绾︿负
200000
鐨勮仛涓佷簩鐑紙鍚堟垚姗¤兌锛夐珮鑱氱墿銆?/p>
The low molecular weight compounds from which the polymers form are known as
monomers. The picture is simply as follows:
褰㈡垚楂樿仛鐗╃殑浣庡垎瀛愬寲鍚堢墿绉颁负鍗曚綋銆備笅闈㈢畝鍗曞湴鎻忚堪涓�涓嬪舰鎴愯繃绋嬶細
butadiene + butadiene + 鈭欌垯鈭?nbsp;+ butadiene
--
鈫?/p>
polybutadiene(4 000 time)
涓佷簩鐑?/p>
锛嬩竵浜岀儻锛嬧�︼紜涓佷簩鐑�斺�斺啋鑱氫竵浜岀儻锛?/p>
4000
娆★級
One can thus see how a substance (monomer) with as small a molecule weight as 54
grow to become a giant molecule (polymer) of (54
脳
4 000
鈮?/p>
)200 000 molecular weight.
鑳藉鐭ラ亾鍒嗗瓙閲忎粎涓?/p>
54
鐨勫皬鍒嗗瓙鐗╄川
锛堝崟浣擄級
濡備綍閫愭笎褰㈡垚鍒嗗瓙閲忎负
200000
鐨勫ぇ
鍒嗗瓙锛堥珮鑱氱墿锛?/p>
銆?/p>
It
is
essentially
the
鈥済iantness鈥?nbsp;
of
the
size
of
the
polymer
molecule
that
makes
its
behavior
(different
from
that
of
a
commonly
known
chemical
compound
such
as