Hydrophilic Polymers - American Chemical Society

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Downloaded by 80.82.77.83 on January 5, 2018 | http://pubs.acs.org Publication Date: January 15, 1996 | doi: 10.1021/ba-1996-0248.pr001

PREFACE JL H E BEHAVIOR of surfactant-modified, water-soluble polymers i n aqueous solutions has b e e n the focus of intensive research efforts. T h i s book reviews recent developments. T h e first section covers hydrogels, w h i c h are l i m i t e d to two u n i q u e p o l y m e r classes. T h e first class consists of totally n e w hydrogels based o n polyphosphazene inorganic compositions; i n the past, these hydrogels have b e e n h y d r o l y t i c a l l y unstable. T h e second class consists of those hydrogels f o r m e d b y h y d r o p h o b e - m o d i f i e d , ethoxylated urethane ( H E U R ) polymers, a f a m i l y that forms hydrogels w h e n the terminal units are f u l l y substituted a n d the p o l y m e r is narrow i n molecular w e i g h t or w h e n the central u n i t is not h y d r o p h o b i c . T h e second section of this book relates to the b i o c o m p a t i b i l i t y and biodégradation of polymers. T h e subtitle of this book c o u l d have been " T h e Importance of O x y e t h y l e n e Segments i n Water-Soluble P o l y m e r s , " for there are o n l y a few chapters i n this text that do not discuss polymers containing oxyethylene segments. T h e a b i l i t y of such polymers to i n h i b i t b l o o d clotting has b e e n an area of past studies, and the role of such polymers i n the behavior of proteins is discussed i n Chapters 3 a n d 4. T h e concern for more biodegradable plastics through the use of natural polymers is c o n s i d e r e d i n Chapters 5 - 8 (a theme i n i t i a l l y addressed i n Agricultural and Synthetic Polymers: Biodegradability and Utilization; J . E d w a r d Glass a n d G r a h a m Swift, E d s . , A C S S y m p o s i u m Series 433, 1990). T h e t h i r d section addresses the characterization a n d aqueous solution properties of h y d r o p h o b e - m o d i f i e d , water-soluble p o l y m e r s . A s sociating block polymers have b e e n studied for a n u m b e r of years, a n d i n the initial stages of these water-soluble polymers, d e t a i l e d analyses were conducted o n poorly d e f i n e d materials. That has b e e n the case i n most of the studies i n h y d r o p h o b e - m o d i f i e d , water-soluble polymers d u r i n g the past decade. I n the subsection o n general concepts, one of the best examples of c o m b i n i n g d e t a i l e d p h y s i c a l analyses o n w e l l characterized water-soluble block polymers is d e s c r i b e d i n C h a p t e r 9. Chapter 10 defines the type of water-soluble polymers obtained i n the different synthetic procedures u s e d i n the p r o d u c t i o n of hydrophobe-modified, water-soluble polymers T h e topics discussed i n clude hydrophobe m o d i f i c a t i o n of h y d r o x y e t h y l c e l l u l o s e ( H M H E C ) , the chain-growth syntheses of h y d r o p h o b e - m o d i f i e d , a l k a l i - s w e l l a b l e emulsions ( H A S E ) and h y d r o p h o b e - m o d i f i e d acrylamide ( R A M ) , a n d the step-growth synthesis of h y d r o p h o b e - m o d i f i e d , ethoxylated urexi Glass; Hydrophilic Polymers Advances in Chemistry; American Chemical Society: Washington, DC, 1996.

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thanes ( H E U R s ) . T h i s chapter is f o l l o w e d b y simulation studies (Chapter 10) of the influence of h y d r o p h o b e placement on the solution properties of H E U R s . T h e s e polymers have f o u n d c o m m e r c i a l acceptance i n architectural coatings, cosmetics, a n d as airplane de-icers. As the applications are broadened to i m p r o v e the environmental acceptance i n applications such as original e q u i p m e n t manufacturing water-borne coatings w h e r e different associative thickeners may be required, the extent of hydration i n b a l a n c i n g the h y d r o p h i l i c - l y o p h i l i c balance of h y d r o p h i l i c polymers w i l l become important. T h e extent of hydration of different polyether diols is discussed i n C h a p t e r 12. Surfactants such as s o d i u m d o d e c y l sulfate interact w i t h poly(oxyethylene) ( P O E ) , but the contribution of the " s t r i n g of p e a r l s " to the viscosity of aqueous solutions has not b e e n quantified. T h i s quantification is done i n Chapter 13. O n e of the most important contributions of associative thickeners i n water-borne coatings is their contribution to higher viscosities at h i g h shear rates. A fundamental study of the influence of shear deformations on the viscosity of surfactants, a prerequisite for understanding the behavior of associative thickeners, is r e v i e w e d i n Chapter 14. T h e solution properties of associative thickeners are discussed i n the second subsection of the associating polymers section. T h e s e discussions i n c l u d e R A M (Chapter 15), the influence of fluoro- vs. hydrocarbon h y d r o p h o b i c units (Chapter 16), a n d H E U R polymers. H E U R thickeners can be synthesized b y a direct a d d i t i o n of monoisocyanates to produce " u n i - H E U R s , " w h i c h p r o v i d e associative thickeners w i t h k n o w n placement a n d molecular-weight control. T h e r h e o l ogy and neutron scattering of u n i - H E U R s are discussed i n Chapters 17 and 18. T h e aggregation numbers and d i f f u s i o n coefficients i n H E U R aqueous solutions are d e t e r m i n e d from N M R measurements i n C h a p ters 19 and 20, a n d their i n f l u e n c e on the b r i d g i n g flocculation of colloidal clusters are presented i n C h a p t e r 21. I n the chapters that f o l l o w the H E U R studies, data on the solution behavior of H M H E C (Chapter 22) a n d H A S E (Chapter 23) thickeners are described. I n the last chapter of this section, the i n f l u e n c e of H A S E , H M H E C , a n d c o m m e r c i a l a n d m o d e l H E U R s i n architectural coating formulations are presented a n d compared i n Chapter 24 w i t h their behavior i n neat and surfactant aqueous solutions g i v e n i n earlier chapters. I n the final chapter, a n e w c o m m e r c i a l , water-soluble p o l y m e r that is not h y d r o p h o b e - m o d i f i e d is discussed. T h i s water-soluble p o l y mer offers a flexible all-carbon backbone w i t h a combination of p e n dant primary amine a n d h y d r o x y l groups. T h i s combination has p r o m ise of d e v e l o p i n g n e w application areas a n d m e e t i n g the needs of older applications w h e r e some existing conventional water-soluble polymers have fallen short. xii Glass; Hydrophilic Polymers Advances in Chemistry; American Chemical Society: Washington, DC, 1996.

Acknowledgments I especially appreciate the work of the reviewers of the i n d i v i d u a l chapters of this text. I gratefully acknowledge financial support from the D i v i s i o n of P o l y m e r i c Materials: Science a n d E n g i n e e r i n g , Inc., of the A m e r i c a n C h e m i c a l Society, Texaco, R o h m a n d Haas, H e r c u l e s , S . C . Johnson, and A i r Products for the speakers i n the s y m p o s i u m from w h i c h the nucleus of this text was d r a w n . T h e next s y m p o s i u m i n this series w i l l be h e l d i n Boston, M A , at the A C S national m e e t i n g the w e e k of August 16,1998. T h o s e w i s h i n g to participate s h o u l d contact me i n the early s p r i n g of that year.

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J. E D W A R D G L A S S

Department of Polymers a n d Coatings North Dakota State U n i v e r s i t y Fargo, ND 58105 September 18, 1995

xii! Glass; Hydrophilic Polymers Advances in Chemistry; American Chemical Society: Washington, DC, 1996.