Showing papers in "Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics in 1989"
TL;DR: The use of 13 carbon nuclear magnetic resonance (NMR) spectroscopy in the molecular characterization of macromolecules has advanced our knowledge into structural areas that have been nearly impossible to measure by other spectroscopic techniques as mentioned in this paper.
Abstract: The use of 13 carbon nuclear magnetic resonance (NMR) spectroscopy in the molecular characterization of macromolecules has advanced our knowledge into structural areas that have been nearly impossible to measure by other spectroscopic techniques. Innovative applications have led to determinations of polymer configurational distributions, comonomer sequence distributions, average sequence lengths, structure and distribution of short chain branches, and analyses of nonreactive end groups. As a result, the importance of 13C NMR to the field of polymer science cannot be overemphasized. The key to the success of 13C-NMR studies in defining polymer molecular structure has been a structural sensitivity which encompasses more than just a few functional groups or carbon atoms. A sensitivity to polymer repeat unit sequences of lengths from two to as many as five, seven, and even nine contiguous repeat units [1,2] has been observed. Of course, any structural technique that senses a unique response from as f...
624 citations
TL;DR: The use of trifluoromethyl substituents for polymeric materials with a unique combination of properties has brought forth a sizable research effort concerning the use of bis-trifluoroacetone (HFA) substituent, particularly the 1,1, 1,3, 3,3-hexafluoroisopropylidene (HFIP) function derived from the incorporation of HFA into the monomer as discussed by the authors.
Abstract: The continuing demand for polymeric materials with a unique combination of properties has brought forth a sizable research effort concerning the use of trifluoromethyl substituents, particularly the 1,1,1,3,3,3-hexafluoroisopropylidene (HFIP) function derived from the incorporation of hexafluoroacetone (HFA) into the monomer. This work had its beginnings approximately 25 years ago when Rogers briefly reported in a patent the preparation of polyimides (PIs) from an hexafluoroisopropylidenebrideged diamine [1,2]. Since then numerous efforts have been made toward the synthesis, characterization, and evaluation of CF3-containing polymers. Much of this information is found in patents, indicating the importance of these polymers to industry. At the present time, at least 11 known classes of polymers containing pendant or backbone-incorporated bis-trifluoromethyl groups have been reported. These polymers show promise as film formers, gas separation membranes, seals, soluble polymers, coatings, and in ot...
143 citations
TL;DR: The first known report of its synthesis was by Grenvesse in 1898 [1] and interest in the synthesis of PPS only began in 1948 when Macallum 121 described the preparation of phenylene sulfide polymers by the melt reaction of p-dichlorobenzene with sodium carbonate and sulfur as mentioned in this paper.
Abstract: Among the various high temperature polymers, those based on aromatic units, such as poly(2, 6-dimethylphenylene oxide) (PPO), poly(pheny1ene sulfide) (PPS), poly(ether ether ketone) (PEEK), and poly(ether sulfone) (PES), have attracted much attention in the last few years due to their good thermal and chemical resistance. One of these polymers, PPS, is also an important high strength/high temperature engineering thermoplastic that is finding increasing use in technological applications such as molding resins, fibers, and matrices for thermoplastic composites. PPS consists of para-phenylene units alternating with sulfide linkages. The first known report of its synthesis was by Grenvesse in 1898 [1]. However, interest in the synthesis of PPS only began in 1948 when Macallum 121 described the preparation of phenylene sulfide polymers by the melt reaction of p-dichlorobenzene with sodium carbonate and sulfur. Further investigation on the synthesis of PPS by Lenz and coworkers [3–5], and later by Edmo...
89 citations
TL;DR: The fastest growing thermoplastic polyesters used extensively for fibers, films, bottles, injection molded parts, and other products are polyethylene terephthalate (PET) as mentioned in this paper.
Abstract: Polyethylene terephthalate (PET) is one of the fastest growing thermoplastic polyesters used extensively for fibers, films, bottles, injection molded parts, and other products.
48 citations
TL;DR: In this paper, the glass transition temperatures of polyimides have been investigated, and the underlying principles involved in a single property such as the transition temperature of a polyimide are discussed.
Abstract: Since polyimides were invented more than 30 years ago, several books dealing with the subject have been published [33, 34, 40u, 48b, 55, 64]. While some of these books [33–35] have very thorough and systematic coverage of the chemistry and general physical, mechanical, and electrical properties of polyimides, most of the literature [40, 48b, 64] is made up of collections of results derived from application-related research on various polyimides. None of the earlier treatises is totally devoted to an understanding of the underlying principles involved in just a single, important property such as the glass transition temperatures of polyimides.
40 citations
TL;DR: The molecular transport of small molecules through polymer films has been the subject of active research over almost three decades as discussed by the authors, and the main thrust in this area is either to accumulate a large body of experimental data to assess the stability of polymer films for extreme serviceability or to develop new theories which describe the phenomenology of transport processes, the latter often being studied in terms of three important parameters: permeation, diffusion, and solubility, in addition to the swelling phenomenon.
Abstract: The molecular transport of small molecules through polymer films has been the subject of active research over almost three decades [1–8]. The main thrust in this area is either to accumulate a large body of experimental data to assess the stability of polymer films for extreme serviceability or to develop new theories which describe the phenomenology of transport processes, the latter often being studied in terms of three important parameters: permeation, diffusion, and solubility, in adition to the swelling phenomenon.
38 citations
TL;DR: In this paper, the molecular weight of nitrocellulose has been studied for over a century and it has been one of the most important factors that needs to be considered in the determination of the nonvolatile content in lacquers.
Abstract: Being one of the oldest known polymers, nitrocellulose has been the subject of study for over a century. It was initially used solely for military purposes; however, since the end of World War I its usage has expanded into the fiber and coatings industries where it has been a mainstay to the present day [1, 2]. General interest in the molecular weight characterization of nitrocellulose may be classified into two categories. The firstand more obvious reason for the relevance of this parameter is that the molecular weight and molecular weight distribution profoundly influence the properties of the product and affect the processability of the material, For instance, the molecular weight (hence, the viscosity of this material) is one of the most important factors that needs to be considered in the determination of the nonvolatile content in lacquers [21]. The second reason is that it is a soluble derivative of cellulose, for which direct molecular weight determination is problematic due to solubility...
14 citations
TL;DR: In this article, a charge transfer polymerization (CTP) was developed, which is a new type of polymerization which has been developed within the last 20 years and its essential character is the interaction between an electron donor (D) and an electron receiver (E).
Abstract: Charge-transfer polymerization is a new type of polymerization which has been developed within the last 20 years. Its essential character is the interaction between an electron donor (D) and an ele...
12 citations
TL;DR: In the past two decades, ylide polymer chemistry has been an area of great interest to chemists due to its theoretical implications and industrial significance as mentioned in this paper. But it has not yet been widely used in practice.
Abstract: Over the past two decades, ylide polymer chemistry has been an area of great interest to chemists due to its theoretical implications and industrial significance.
8 citations