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This volume Macromolecular Engineering: Recent Advances has been developed based on the 1 st International Conference on "Advanced Polymers Via Macromolecular Engineering" (APME '95), June 24-29, 1995 at the Vassar College campus, Poughkeepsie, New York. In APME '95, 100 oral and over 50 poster presentations are to be delivered from scientists around the globe. The scientific program covers recent advances in macromolecu­ lar engineering. It is our vision that the knowledge of the past and the promise of the future are blended together in APME '95 to enrich and stimulate the scientists, which will bring about the progress of macromolecular engineering. Scientists from over 30 countries will be joining together to share this vision. Although over 150 papers are to be presented in APME '95 conference, we could not include all the papers in this book for a variety of reasons, most importantly the authors willingness to contribute to this volume in time to meet the deadline. However, the 24 comprehensive chapters included in this volume are a true reflection of some of the important themes of macromolecular engineering that are part of the APME '95 conference. We believe macromolecular engineering is the key to developing new polymeric materials and, to this end, it is hoped this volume will aid in this introspection.



Group Transfer Polymerization and Its Relationship to Other Living Systems

1. Group Transfer Polymerization and Its Relationship to Other Living Systems

The large number of organic function groups that can be attached to the ester function of methacrylate and acrylate monomers makes this series of monomers attractive for synthesis of polymers with diverse properties. When this diversity of functionality is coupled with living polymerization techniques the range of new product possibilities is staggering. Polymer synthesis chemists have therefore been searching for living polymer systems for methacrylates and acrylates that operate at above ambient temperature, use reasonably low cost initiators, tolerate moderate amounts of impurities, control chain tacticity and allow the functionality that is to be introduced to survive the polymerization process.
Owen W. Webster

2. Fundamentals and Practical Aspects of “Living” Radical Polymerization

Living radical polymerization is very difficult if not impossible to realize. Complete elimination of chain breaking reactions, especially termination, is not possible in radical processes. Therefore quotation marks are used for a term of “living” radical polymerization. However, well-defined polymers with predetermined molecular weights, low polydispersities and terminal functionalities as well as block copolymers can be prepared via radical polymerization. Thus, although complete suppression of termination is not possible, preparation of controlled polymers with relatively low molecular weights has been successful. In this article fundamentals and some practical synthetic aspects of controlled radical polymerization will be discussed.
Krzysztof Matyjaszewski

Living Carbocationic Copolymerizations

3. The Constant Copolymer Composition Technique

The Constant Copolymer Compositon (CCC) technique readily produces copolymers with constant (homogeneous) macro-and microcompositions (microstructures) even from monomer pairs with significantly different reactivities, for example with monomers whose reactivity ratios differ by an order of magnitude. The CCC technique eliminates the compositional drift along copolymer chains which always arise in copolymers made by batch or forced ideal techniques and necessarily lead to inhomogeneous often ill-defined products. In the CCC technique a stream of comonomers is fed continuously to the active copolymerization charge such that the composition of the feed and the rate of feed addition are respectively equal to the composition of the copolymer produced and the rate of copolymerization. The fundamentals of the CCC technique together with a detailed quantitative analysis are presented, and the differences of the conventional and CCC techniques are discussed and illustrated with the industrially important isobutylene-p-methylstyrene copolymerization system.
A. Nagy, I. Országh, J. P. Kennedy

Living Carbocationic Copolymerizations

3. Application of the Constant Copolymer Composition Technique for the Synthesis of Isobutylene/ p-Methylstyrene Copolymers

Compositionally uniform high molecular weight isobutylene (IB)/p-methylstyrene (pMeSt) copolymers have been prepared by using the constant copolymer composition (CCC) technique (see preceding publication) under living carbocationic copolymerization (LC⊕Copzn) conditions. The attainment of the desired copolymer composition of IB/pMeSt = 96.5/3.5 mol%/mol% was demonstrated up to \(\overline {{{M}_{n}}} \approx 65,000 g \cdot mo{{l}^{{ - 1}}} \) Мп ≈65,000 g.mol- 1. CCC and LC⊕Copzn conditions have been quantitated by three diagnostic plots, i.e., two plots that prove the attainment of CCC conditions and one that indicate the existence of LCCopzn. Specifically, CCC conditions were demonstrated by a rate plot which shows comonomers input together with copolymer formed as a function of time, and a composition plot which shows feed composition together with copolymer composition as a function of copolymer formed (Wp); finally living copolymerization was demonstrated to proceed by plotting \( {\overline M _n}\) Мп (number average molecular weight) as a function of W. According to this three prong evidence uniform composition IB/pMeSt copolymers with up to \(\overline {{{M}_{n}}} \approx 65,000 g \cdot mo{{l}^{{ - 1}}} \) Мп ≈65,000 g.тo1-1 can be conveniently prepared by living copolymerization under readily achievable CCC conditions at -50 °C. This is the first demonstration of the synthesis of a uniform composition binary copolymer by LC⊕Copzn from a comonomer pair whose reactivity ratios differ by about one order of magnitude.
I. Országh, A. Nagy, J. P. Kennedy

4. Hexaarmed Polystyrene Stars from a Newly Designed Initiator of Carbocationic Polymerization

A novel hexafunctional initiator C6[(CH2)2p-C6H4CH(Cl)Me]6 has been purposely synthesized to subsequently serve in the cationic polymerization of styrene. This initiator is prepared via Fe(ŋ-C5H5)+ mediated perbenzylation of hexamethylbenzene, followed by regiospecific acetylation, reduction and chlorination of outer phenyl rings. The polystyrene stars which are obtained in the presence of this initiator exhibit narrow molecular weight distribution (MWD) and a precise functionality of 6. Because the cationic polymerization of styrene is not totally free of side reactions, such as ß-proton elimination of growing carbeniums, the upper limit of the molecular weight control for these star polymers is the range of Mn ~30000 g/mole.
Eric Cloutet, Jean-Luc Fillaut, Didier Astruc, Yves Gnanou

5. Photoinitiation of Ionic Polymerizations

At present, there is growing interest in industrial applications of photopolymerizations which refers mainly to surface coating processes proceeding via free radical mechanisms [1]. However, acrylate-and methacrylate-based formulations which are largely employed for this purpose exhibit disadvantages due to shrinkage and incomplete monomer conversion. It is hoped to overcome these problems with the aid of formulations containing substances of different chemical nature such as compounds containing epoxide groups. However, the latter can be polymerized only cationically and, therefore, the photoinitiation of cationic polymerizations has recently been the subject of intense investigations at various places in the world [2,3].
Wolfram Schnabel

6. Synthesis and Photopolymerization of 1-Propenyl Ether Monomers

A variety of mono-, di-, and multifunctional 1-propenyl ethers were readily prepared in high yields by the condensation of alcohols with allyl halides followed by the base or transition metal catalyzed rearrangement of the resulting allyl ethers. These monomers in general display very high reactivity in cationic polymerizations. In our work, we have focused on photoinduced cationic polymerizations of these monomers using diaryliodonium and triarylsulfonium salt photoinitiators. To study these very fast photopolymerizations, extensive use of differential photoscanning calorimetry and real-time infrared spectroscopy were made. Employing these techniques, the effects of monomer and photoinitiator structure on the rates of polymerization were studied.
J. V. Crivello, K. D. Jo, W.-G. Kim, S. Bratslavsky

7. Design of Macromolecular Prodrug Forms of Antitumor Agents

In recent years, many drugs having high potential were synthesized or purified. Therefore, drug delivery systems (DDS) which allow such new drugs to perform up to their potentials, became more and more important. DDS are the systems ideally devised to disseminate a drug when and where it is needed, and at minimum dose levels.
Tatsuro Ouchi

8. Transparent Multiphasic Oxygen Permeable Hydrogels Based on Siloxanic Statistical Copolymers

Highly oxygen permeable siloxanic hydrogels with Dk up to 170. 10-11 сm3(O2) cm cm-2 · s-1· mmHg-1 and 20–30 wt% hydration can be obtained by copolymerization of acrylic acid (AA) with tris(trimethyl siloxy) γ methacryloxy propylsilane) (IRIS) or dimethacryloxybutyl polydimethylsiloxane (DMPDMS). Optical properties of these materials depend directly on size of hydrophilic demixed domains as it had been shown by small angle neutron scattering experiments.
C. Robert, C. Bunel, M. A. Dourges, J. P. Vairon, F. Boué

9. Preparation of Tubular Polymers from Cyclodextrins

In recent years, polymers having unique structures, such as comb like polymers1, double helical polymers2, dendrimers3, and polymers with bilayer membranes structures4, have been prepared and attracted much attention because of their unique properties and functions. Much effort has been devoted to obtain other polymers with unique structures. In spite of strenuous efforts, tubular polymers have not been obtained until recently. Tubular polymers are ubiquitous in nature, especially in the living systems. Microtubules, flagella, and ion channels have tubular structures of various sizes. Tubular polymers in the living systems have various functions, not only as channels for membranes, but also as devices for mechanical movements. However, there have been no synthetic tubules made of organic materials of manometer size.
Akira Harada, Jun Li, Mikiharu Kamachi

10. Multi-Component Polymers Containing Polyisobutylene Via Multi-Mode Polymerization

Recently, the trend in polymer research has been geared toward producing advanced materials via macromolecular engineering [1]. It is known that a desired combination of physical properties could be achieved by designing tailor made block and graft copolymers. Various methods including polycondensation reactions (using telechelic oligomers) or living polymerization techniques have been used for the synthesis of multi-component polymers. Although telechelic oligomers can be made by a wide variety of techniques, their use in block copolymerization suffer from a number of disadvantages. It is known that sequential monomer addition (SMA) technique in living ionic polymerization [2] is a convenient way to prepare block copolymers possessing well-defined and predetermined structures. In addition to well established living anionic polymerization, cationic living polymerization of isobutylene has been developed during the past few years [3–8]. Well defined block copolymers are prepared by these living systems following the common strategy of SMA [7]. It should be pointed out that there are various drawbacks which quite often retards the practical application of living systems to prepare block copolymers. These drawbacks essentially relate to limitation of the method to certain monomers and exclude monomers that polymerize by other mechanisms.
Munmaya K. Mishra

11. Macrophotoinitiators

Synthesis and Their Use in Block Copolymerization
There has been growing interest in the preparation of polymeric photoinitiators [1]. They present several atractive aspects over low molecular weight counterparts including low volatility and migration. As far as migration is concerned, their value in UV curing associated with food packing will be more important since future legislation will require photoinitiating systems with zero migration. Besides UV curing applications, block and graft copolymers can be prepared by using main and side chain polymeric photoinitiators, respectively [2]. These systems consists of a photochemical reactions by which active sites are produced at the chain ends or side chains, which themselves initiates the polymerization of a second monomer.
Yusuf Yağci

12. Amphiphilic Polymer Networks by Copolymerization of Bis-Macromonomers

Polymers carrying a polymerizable end group, generally known as macromonomers, have frequently been utilized for the synthesis of graft copolymers (1)(2). When a polymer contains polymerizable groups at both chain ends, -a bis-macromonomer-, polymerization or copolymerization leads to the corresponding networks or segmented copolymer networks respectively. The physicochemical properties of the latter may be expected to be the result of a combination of the properties of segmented polymers at the one hand and of polymer networks at the other. For example, it should be interesting to investigate the morphology of such compounds if they are build up of two incompatible chain segments. The theory of the segmented copolymers would predict a phase separation, the morphology of which is determined by the relative lengths of the two constituting polymers. However, in the network form, phase separation is inhibited due to the restricted chain mobilities and therefore a compatibilization of two incompatible polymers may be expected. As a consequence, new materials with formerly unreachable physicochemical properties could arise.
Peiwen Tan, Saskia R. Walraedt, Jan M. M. Geeraert, Eric J. Goethals

13. Stereospecific Polymerization and Copolymerization of Stereoregular PMMA Macromonomers

It is one of the most effective methods for the structural control of comblike polymer and graft polymer to utilize macromonomers. In fact, many papers have been published on utilization of macromonomers for the preparation of comblike polymers and graft polymers with controlled structures1–17). However, few investigations have been reported on the preparation of comblike polymer and graft polymer with high stereoregularity. We have reported the preparation of isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate) (РММА) macromonomers with styrene end group, polymerizations of which give comblike polymers with stereoregular PMMA branches6–11). We have also reported the stereospecific anionic polymerization of polyisobutylene macromonomer having methacryloyl end-func-tion, which afforded comblike polymers with stereoregular main chainI2) The reason why methacryloyl group was selected as a polymerizable function in this case is that the stereoregularity of polymethacrylate can be controlled in a wide range by selecting a proper initiator and polymerization conditions18,19).
Koichi Hatada, Tatsuki Kitayama, Osamu Nakagawa, Takafumi Nishiura

14. Acrylic Graft Copolymers Via Macromonomers

Synthesis and Characterisation
Comb-shaped poly(methyl methacrylate) (PMMA) and PMMA grafted with poly(nbutyl acrylate) (PnBuA) were prepared by radical copolymerisation of ω-methacryloyl-PMMA with MMA and nBuA, respectively. The comb-shaped PMMA is characterised with respect to radius of gyration by using GPC equipped with a multi-angle laser light scattering detector. The radical copolymerisation of the macromonomer with nBuA in toluene follows complex kinetics. The dependence of the relative reactivity of the macromonomer on absolute concentration and on the ratio of comonomers may be explained by preferential solvation of comonomers by segments of their own kind (“bootstrap effect”) or even micelle formation. However, there is no clear evidence for the formation of micelles in toluene. In contrast, NMR studies show micelle formation in the preferential solvent DMSO. The graft copolymers are transparent thermoplastic elastomers. Phase separation is demonstrated by DSC and morphological studies.
Wolfgang Radke, Sebastian Roos, Helga M. Stein, Axel H. E. Müller

15. Anionic Synthesis of Macromonomers and Graft Copolymers with Well-Defined Structures

Macromonomers are linear macromolecules carrying some polymerizable functional groups at their chain ends; the polymerizable functional groups can be at one chain end or at both chain ends1–12. Macromonomers are macromolecular monomers, often referred to as “Macromers®”1. The important feature of macromonomers is that they can undergo copolymerization with other monomers by a variety of mechanisms to form comb-type, graft copolymers13,14 as shown in Scheme 1. This aspect of macromonomers distinguishes them from telechelic (α,ω-difunctional) polymers5,8; telechelic polymers undergo step-growth type chain extension reactions with other monomers to form linear macromolecules, not branched structures. The polymerizable functional group at the chain end of a macromonomer is often a vinyl group, 1, but it can also be a heterocyclic ring such as an oxirane (epoxide) functionality, 2. These functional groups participate in chain reaction polymerizations with other vinyl or heterocyclic monomers, respectively. A condensation-type macromonomer has two functional groups at one chain end (3) which can participate in step-growth (condensation) polymerization with other difunctional monomers; for example, the functional group, X, could be hydroxyl, amino, carboxyl or isocyanate5,9.
Roderic P. Quirk, Qizhuo Zhuo, Yuhsin Tsai, Taejun Yoo, Yuechuan Wang

16. New Superstructures from Block and Graft Copolymers with Precisely Controlled Chain Architecture

Polymers have a high potential as structural and functional materials. However, synthetic polymer systems are still far away from the elegant schemes of biological systems in self-organization phenomena and the formation of complex structures with specific functions. In biopolymeric systems, the supramolecular structure results from a special sequence of amino acids along the polypeptide chain and/or periodical sequences of other building units along the chain, resulting in highly organized structures which in most cases are dtabilized by hydrogen bond formation or ionic interactions. Unique materials with extraordinary ultimate properties result, and it is a challenging question, if and/or to which extent this can be transfered over to synthetic macromolecules.
C. D. Eisenbach, A. Göldel, H. Hayen, T. Heinemann, U. S. Schubert, M. Terskan-Reinold

17. Molecular Organization of Polystyrene and Polymethylmethacrylate with Fluorocarbon Side Chains

Polystyrene and polymethylmethacrylate with perfluoroalkyl side chains, F(CF2)n(СН2)m have been prepared and studied with respect to structure formation and utilization for oil and water repellent coatings. As the length of the side chains exceeds n=4 and m=2, the polymers crystallize in bilayers which itself form a multilayered structure. Solution casting yielded spontaneous assembling of the bilayers parallel to the substrate plane and gave laminate coatings. Very low critical surface tension values were determined by dynamic contact angle measurements. IR absorption and X-ray photoelectron spectroscopy revealed a highly ordered layer of fluorocarbon segments at the air/polymer interface. This is consistent with scanning force microscopy measurements showing a surface formed by regularly packed CF3-groups. Anisotropic variations of the linear spacing in directions parallel and perpendicular to the layers were detected by X-ray diffraction measurements at elevated temperatures and upon a glass transition.
Sergei Sheiko, Alexei Turetskii, Jens Höpken, Martin Möller

18. Synthesis of 1–10 Micron Polymer Particles by the New Grafting-Precipitation Method (GPM)

In the technology of polymer synthesis in heterogeneous (preferentially aqueous) media, the techniques of emulsion-and suspension polymerisation are well known (10). Emulsion polymerisation results in very small polymer particles (size 0.06–0.2 µm) and suspension polymerisation yields much larger polymer particles (size ≥20 µm).
W. De Winter, D. Timmerman, R. Declercq

19. Design and Control of the Structure of Polymers and Molecular Aggregates in the Solid Lattice: Synthetic and Self-Assembly Approach

Synthetic and Self-Assembly Approach
The design and synthesis of oligomers and polymers with a well-defined structure has shown considerable success in recent years [1,2]. However, to fine tune the structure of a macromolecule and to obtain the desired electronic, photonic and thermal properties which are often the direct result of macroscopic order of molecules in the solid lattice, remains to be a challenge [3]. Two approaches are pursued towards designing polymers with well-defined structure. The first method rests on the careful choice of a monomer with multiple functional groups. This is particularly important for the synthesis of defect-free double stranded ladder-type polymers. The second method explores the self-assembly of small molecules and polymeric materials to form supramolecular structures. Here, the weak intermolecular interactions, such as hydrogen bonding and van der Waals forces, are used to tune the structural organization of the self-complementary molecular components. Both of these approaches have been exploited by many research groups [4,5].
S. Valiyaveettil, U. Scherf, V. Enkelmann, M. Klapper, K. Müllen

20. Polyaddition of H3PO4, and Its Derivatives to Diepoxides Via Activated Monomer Mechanism

Polymer Structures and Functionalization
The cationic polymerization of cyclic ethers, esters, imines and amides proceeds in the presence of compounds containing an active hydrogen atom (e.g. -OH) by the activated monomer mechanism, first introduced for the polymerization of cyclic ethers in 1984 [1].
S. Penczek, P. Kubisa, A. Nyk

21. Functional Polymers with Various Macrocyclic Chain Architectures and Well-Defined Dimensions

Natural macrocycles represent a broad class of medium to large size molecules which actively contribute to numerous biological and chemical processes. Their cyclic architecture, generally associated to a special arrangement of comonomer units allow them to play very specific and sophisticated roles in complex reaction pathways. For example, Valinomycin shown in Figure 1 possesses inner/outer amphiphilic ring chain properties which makes it able to complex organic alkali salts. It may be regarded as one of the natural forerunners of large size crown ethers. Amphotericin, Figure 2a, presents an amphiphilic diblock-type cyclic architecture. The latter allows the formation of ion channels across biological membranes through which salts can be transported. Via this function Amphotericin can manifest antibiotic properties. Other large size macrocycles with a distinct diblock-type amphiphilic structure are also found in living systems. The one shown in Figure 2b, is a constituent of the lipidic membrane of bacteria which grow in very hard conditions (pH=2, 85°C), thus suggesting that cell wall stability can be reinforced by cyclic molecular architecture.
Alain Deffieux, Michel Schappacher, Laurence Rique-Lurbet

22. Functionalized Polymers

Synthesis and Modification
Polymers bearing reactive groups are of great scientific and economical interest. Even since the beginning of macromolecular chemistry, functional groups of biopolymers, e.g. of proteins, cellulose or rubber, have been modified chemically to control e.g. processibility, mechanical properties or solubility. Additionally, in the last several decades, many synthetic polymers bearing functional groups have been partially responsible for the rapid development of markets for tailor made organic materials. Recent demands to increase the degree of polymer recycling have also enhanced some developments of polymers containing functional groups for enzymatical or chemical degradation.
Helmut Ritter

23. Polymers with Triazene Units in the Main Chain

Application for Laser-Lithography
Several monomeric and polymeric triazenes have been synthesized and characterized by common methods such as 1H NMR-, IR-, Raman-, UV-spectroscopy, DSC, and GPC. Their thermolysis, photosensitivity, and the effect of H3O+ on their stability have been studied in detail, since those characteristics are very important for an application of these compounds in microlithography.
In laser ablation experiments, polymers containing triazene units in the main chain (TP1 - ТР9) exhibited several advantages over systems in which common polymers (e.g. PMMA) are doped with low molecular triazenes (T1- Т14) especially the fact that their ablation craters have clean contours and sharp edges is of great interest for this type of microstructering.
Oskar Nuyken, Jürgen Stebani, Alexander Wokaun, Thomas Lippert

24. Synthesis and Properties of Poly(Aryl Ether Ketone) Possessing Crosslinking Groups

Application for Electronic Device
Fully aromatic poly(ether ketone)s (PEKs) are widely used as high-performance engineering plastics in various industrial fields because of their excellent thermal and chemical stabilities, and mechanical properties at high temperature (May, 1986). A non-sub-stituted PEK is generally insoluble in organic solvents at room temperature because it shows highly crystalline property. This often restricts the use of the PEK for some applications.
Yoshihiro Taguchi, Hiroshi Uyama, Shiro Kobayashi, Katsuhisa Osada


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