TABLE OF CONTENTS Polyols used in polyurethane manufacture are divided from the structural point of view in two groups. In the first group there are the low molecular weight (MW) polyols, very well described in organic chemistry, having unitary and concrete MW, such as: propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, 1,4 butanediol, neopentyl glycol, triethanolamine, glycerol, etc. These polyols are currently used in the polyurethane fabrication as chain extenders (the polyols with two hydroxyl groups/mol called diols) or as crosslinkers (the polyols with more than two hydroxyl groups/mole such as triols, tetraols, etc.). Because these polyols are very well characterised and the chemistry and technology of these compounds is well known [1, 2], this chapter does not cover this group.
The second group of polyols for polyurethane contains low MW polymers (oligomers with a maximum MW of 10,000 daltons) with terminal hydroxyl groups (hydroxy telechelic oligomers), called oligo-polyols, characterised by an average molecular weight and having a molecular weight distribution (MWD) of homologous species. The present chapter is dedicated exclusively to this second group of oligo-polyols for polyurethanes, which together with isocyanates are the most important raw materials to build the complex architecture of a polyurethane polymer [3-12].
The general formula of an oligo polyol for polyurethane is shown in Figure 3.1:
An oligo-polyol for polyurethanes, may have two, three, four, five, six, seven or a maximum of eight hydroxyl groups/mol. Polyols with a higher number of hydroxyl groups/mol are rarely...
