Thermostability of poly(p‐hydroxystyrene) blends with poly(vinyl pyrrolidone) and poly(ethyl oxazoline)

Themostability of Poly(p-Hyhxystyrene) Blends with Poly(viny1 @rmlidone) and Poly(ethy1 Oxaxoline)It is generally accepted that interchain hydrogen bonding restricts segment mobility and alters the glass transition temperatures and viscoelastic responses of p~lymers.l-~On the other hand, the attendant changes in the thermal stabilities of some polymers are not completely understood.Bare found that hydrophilic groups introduced into the aromatic ring increased the thermal stability of polymers.Still and Whitehead6v7 found the pyrolysis behavior of poly(hydr0xystyrene), PHS, in the temperature range of 300-500°C to be different from that of polystyrene.Whether interpolymer hydrogen bonding in a blend w i l l result in the alteration of thermal stability is an open question.As early as 1959, it was reported that blends of poly(acrylic acid) and poly(ethy1ene oxide) containing 30-701g of the latter exhibited better thermal stability than either component polymer!PHS is miscible with poly(viny1 pyrrolidone) (PVP) and poly(ethy1 oxazoline) (PEOx), and the driving force for miscibility can be attributed to hydrogen-bonding interaction between the donor polymer PHS and the acceptor polymers.In this communication we wish to report preliminary results of an investigation of the thermal stability of these blends.Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were used to determine weight loss and chemical changes. EXPERIMENTALPHS was prepared by hydrolysis' of poly(p-acetoxystyrene) (MW 5 x lo5) which was polymerized from p-acetoxystyrene (courtesy of Celanese Co.) by free radical initiator.The polymer was purified by precipitation twice from methyl ethyl ketone solution into a large excw of hexane.P W (MW 3.6 X lo5) and PEOx (MW 5 X lo5) were obtained from Aldrich Co. and Dow Chemical Co., respectively.