Pub Date : 1998-01-01DOI: 10.1080/15583729808546035
K. Subramanian
1. INTRODUCTION In recent years, increasing research interest has been focused on the chemistry of inorganic polymers such as polysilanes, polygermanes, and the like based on the saturated linear skeletons of group 4 atoms. Among these, polymeric organosilicon compounds, namely, polysilanes having the catenation in its backbone, are studied [1–8] extensively because of their commercial functional uses, such as (1) a precursor for β-SiC fiber, a versatile impregnating agent [9, 10] for strengthening ceramics; (2) protective coatings [11] for carbon-carbon composites and coatings resistant to atomic oxygen [12] and the like; (3) radical photoinitiators [4]; (4) photoconductors [13, 14] for electrophotography and nonlinear optical materials [15, 16]; and (5) production of conducting and semiconducting [17] electronic devices. These applications are associated with their different chemical and σ-conjugated electronic behavior due to the unusual mobility of σ-electrons compared to most other inorganic and orga...
{"title":"A Review of Electrosynthesis of Polysilane","authors":"K. Subramanian","doi":"10.1080/15583729808546035","DOIUrl":"https://doi.org/10.1080/15583729808546035","url":null,"abstract":"1. INTRODUCTION In recent years, increasing research interest has been focused on the chemistry of inorganic polymers such as polysilanes, polygermanes, and the like based on the saturated linear skeletons of group 4 atoms. Among these, polymeric organosilicon compounds, namely, polysilanes having the catenation in its backbone, are studied [1–8] extensively because of their commercial functional uses, such as (1) a precursor for β-SiC fiber, a versatile impregnating agent [9, 10] for strengthening ceramics; (2) protective coatings [11] for carbon-carbon composites and coatings resistant to atomic oxygen [12] and the like; (3) radical photoinitiators [4]; (4) photoconductors [13, 14] for electrophotography and nonlinear optical materials [15, 16]; and (5) production of conducting and semiconducting [17] electronic devices. These applications are associated with their different chemical and σ-conjugated electronic behavior due to the unusual mobility of σ-electrons compared to most other inorganic and orga...","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"44 1","pages":"637-650"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87462799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808546030
S. Ramesh, K. Tharanikkarasu, G. Mahesh, G. Radhakrishnan
1. INTRODUCTION In the increasingly changing scenario in which yesterday's luxuries have become today's necessities, polymers have played a very crucial role. From ships to aircraft, polymeric materials have found tremendous applications, often having many desirable properties compared to many conventional materials. Polyurethanes (PUs) belong to one such class of materials used for all-around applications. Polyurethanes are an important class of block copolymers for which the properties of the end product can be designed according to user needs. Due to the potential large volume of applications and the high versatility of properties, these materials require a thorough understanding of synthesis and properties, as well as updating of knowledge. The manufacture of polyurethanes involves a greater degree of control over chemical reactions than most other polymers do. Their properties range from liquid, soft, and rubbery solids to rigid thermoplastic and thermoset materials [1–8].
{"title":"Synthesis, Physicochemical Characterization, and Applications of Polyurethane Ionomers: A Review","authors":"S. Ramesh, K. Tharanikkarasu, G. Mahesh, G. Radhakrishnan","doi":"10.1080/15583729808546030","DOIUrl":"https://doi.org/10.1080/15583729808546030","url":null,"abstract":"1. INTRODUCTION In the increasingly changing scenario in which yesterday's luxuries have become today's necessities, polymers have played a very crucial role. From ships to aircraft, polymeric materials have found tremendous applications, often having many desirable properties compared to many conventional materials. Polyurethanes (PUs) belong to one such class of materials used for all-around applications. Polyurethanes are an important class of block copolymers for which the properties of the end product can be designed according to user needs. Due to the potential large volume of applications and the high versatility of properties, these materials require a thorough understanding of synthesis and properties, as well as updating of knowledge. The manufacture of polyurethanes involves a greater degree of control over chemical reactions than most other polymers do. Their properties range from liquid, soft, and rubbery solids to rigid thermoplastic and thermoset materials [1–8].","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"8 1","pages":"481-509"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89449115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808544528
Enrique Saldícar, P. Dafniotis, W. Ray
Emulsion polymerization processes have important advantages over bulk and solution processes, such as the production of polymer of higher molecular weights at high polymerization rates and easier temperature control due to the low viscosity of the reaction media.
{"title":"Mathematical Modeling of Emulsion Copolymerization Reactors. I. Model Formulation and Application to Reactors Operating with Micellar Nucleation","authors":"Enrique Saldícar, P. Dafniotis, W. Ray","doi":"10.1080/15583729808544528","DOIUrl":"https://doi.org/10.1080/15583729808544528","url":null,"abstract":"Emulsion polymerization processes have important advantages over bulk and solution processes, such as the production of polymer of higher molecular weights at high polymerization rates and easier temperature control due to the low viscosity of the reaction media.","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"141 1","pages":"207-325"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80108084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808546028
E. Kenawy
1. INTRODUCTION Agrochemicals are bioactive agents concerned with the utilization of chemicals to improve production of crops for a plentiful and high-quality food supply for consumers. Hence, a great increase in the quantities of these chemicals is necessary for enhancing any substantial increase in farm production of foodstuffs [1]. However, considering the present method of growing foodstuffs, we cannot both increase farm output and ensure a high-quality environment [2]. Depending on the method of application and climatic conditions, as much as 90% of conventionally applied agrochemicals never reach their objectives: to produce the desirable biological response at the precise time and in the quantities required [3].
{"title":"Recent Advances in Controlled Release of Agrochemicals","authors":"E. Kenawy","doi":"10.1080/15583729808546028","DOIUrl":"https://doi.org/10.1080/15583729808546028","url":null,"abstract":"1. INTRODUCTION Agrochemicals are bioactive agents concerned with the utilization of chemicals to improve production of crops for a plentiful and high-quality food supply for consumers. Hence, a great increase in the quantities of these chemicals is necessary for enhancing any substantial increase in farm production of foodstuffs [1]. However, considering the present method of growing foodstuffs, we cannot both increase farm output and ensure a high-quality environment [2]. Depending on the method of application and climatic conditions, as much as 90% of conventionally applied agrochemicals never reach their objectives: to produce the desirable biological response at the precise time and in the quantities required [3].","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"2 1","pages":"365-390"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81578497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808546032
M. Coote, T. P. Davis, B. Klumperman, M. Monteiro
1. INTRODUCTION The ability of solvents to affect the homopropagation rate of many common monomers has been widely documented. For example, Bamford and Brumby [1] showed that the propagation rate kp of methyl methacrylate (MMA) at 25°C was sensitive to a range of aromatic solvents. Burnett, Cameron, and Joiner [2] found that the kp of styrene (Sty) was depressed by increasing concentrations of benzonitrile, bromobenzene, diethyl phthalate, dinonyl phthalate, and diethyl malonate, while in other studies [3, 4], they found that the kp for MMA was enhanced by halobenzenes and naphthalene. More recent work by Zammit et al. [5] has shown that solvents capable of hydrogen bonding, such as benzyl alcohol and N-methyl pyrrolidone, have a small influence on both the activation energy Ea and preexponential factor A in Sty and MMA homopropagation reactions. These are but a few of the many instances of solvent effects in the homopolymerization reactions of two typical monomers, Sty and MMA. For these monomers, solven...
{"title":"A mechanistic perspective on solvent effects in free-radical copolymerization","authors":"M. Coote, T. P. Davis, B. Klumperman, M. Monteiro","doi":"10.1080/15583729808546032","DOIUrl":"https://doi.org/10.1080/15583729808546032","url":null,"abstract":"1. INTRODUCTION The ability of solvents to affect the homopropagation rate of many common monomers has been widely documented. For example, Bamford and Brumby [1] showed that the propagation rate kp of methyl methacrylate (MMA) at 25°C was sensitive to a range of aromatic solvents. Burnett, Cameron, and Joiner [2] found that the kp of styrene (Sty) was depressed by increasing concentrations of benzonitrile, bromobenzene, diethyl phthalate, dinonyl phthalate, and diethyl malonate, while in other studies [3, 4], they found that the kp for MMA was enhanced by halobenzenes and naphthalene. More recent work by Zammit et al. [5] has shown that solvents capable of hydrogen bonding, such as benzyl alcohol and N-methyl pyrrolidone, have a small influence on both the activation energy Ea and preexponential factor A in Sty and MMA homopropagation reactions. These are but a few of the many instances of solvent effects in the homopolymerization reactions of two typical monomers, Sty and MMA. For these monomers, solven...","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"23 1","pages":"567-593"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82331269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808546034
D. Musale, S. S. Kulkarni
1. INTRODUCTION The major limitations for application of ultrafiltration (UF) processes are the membrane fouling and concentration polarization phenomena arising from rejection of solute molecules at the membrane surface. Concentration polarization can be controlled by engineering parameters such as module design and system hydrodynamics, whereas fouling is influenced by various membrane-solute interactions, membrane morphology, and solute-solute interactions. Studies of the membrane surface chemistry and solution environment, which are responsible for membrane-solute interactions, are important for understanding membrane performance and fouling during UF.
{"title":"Effect of Membrane-Solute Interactions on Ultrafiltration Performance","authors":"D. Musale, S. S. Kulkarni","doi":"10.1080/15583729808546034","DOIUrl":"https://doi.org/10.1080/15583729808546034","url":null,"abstract":"1. INTRODUCTION The major limitations for application of ultrafiltration (UF) processes are the membrane fouling and concentration polarization phenomena arising from rejection of solute molecules at the membrane surface. Concentration polarization can be controlled by engineering parameters such as module design and system hydrodynamics, whereas fouling is influenced by various membrane-solute interactions, membrane morphology, and solute-solute interactions. Studies of the membrane surface chemistry and solution environment, which are responsible for membrane-solute interactions, are important for understanding membrane performance and fouling during UF.","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"85 1","pages":"615-636"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75394280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808544527
Feng-cai Lu
Aromatic heterocyclic polymers and polysiloxanes exhibit excellent thermal, mechanical, and insulating properties, having both wide and good potential use as multipurpose structural and functional materials in aerospace, electronic, manufacturing, and chemical industries. This paper briefly reviews our research work on several important aromatic heterocyclic polymers: polyphenylquinoxalines (PPQs), polytriazines (PPTs), polypyrrolones (PYs), polyimides (PIs), polyamide-imides (PAIs), polybenzimidazoles (PBIs); and polysiloxane. Either all or some of them can meet the needs in the above-mentioned high-technology areas. It is believed that the research work and applications of these polymers will be continually developed in the future. We focused our attention on (1) the syntheses of new monomers and polymers; (2) development of new synthetic routes; (3) discovery of new properties of polymers; (4) modification of monomer casting nylon (MC nylon, polycaprolactam) by these polymers and even heterocyclic comp...
{"title":"Some Heterocyclic Polymers and Polysiloxanes","authors":"Feng-cai Lu","doi":"10.1080/15583729808544527","DOIUrl":"https://doi.org/10.1080/15583729808544527","url":null,"abstract":"Aromatic heterocyclic polymers and polysiloxanes exhibit excellent thermal, mechanical, and insulating properties, having both wide and good potential use as multipurpose structural and functional materials in aerospace, electronic, manufacturing, and chemical industries. This paper briefly reviews our research work on several important aromatic heterocyclic polymers: polyphenylquinoxalines (PPQs), polytriazines (PPTs), polypyrrolones (PYs), polyimides (PIs), polyamide-imides (PAIs), polybenzimidazoles (PBIs); and polysiloxane. Either all or some of them can meet the needs in the above-mentioned high-technology areas. It is believed that the research work and applications of these polymers will be continually developed in the future. We focused our attention on (1) the syntheses of new monomers and polymers; (2) development of new synthetic routes; (3) discovery of new properties of polymers; (4) modification of monomer casting nylon (MC nylon, polycaprolactam) by these polymers and even heterocyclic comp...","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"79 1","pages":"143-205"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80144477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-01-01DOI: 10.1080/15583729808546031
P. Dubois, M. Alexandre, François Hindryckx, R. Jerome
1. INTRODUCTION Dispersions of inorganic fillers within polymers are commonly designated as polymer-based composites. The properties of these materials are isotropic or anisotropic, depending on the geometry of the filler particles and the effect of the processing conditions on their orientation. Fillers are used to improve some physicomechanical properties of the polymer, the material processability, or decrease the final cost [1]. As a typical example, highly filled composites in which the filler concentration approaches the maximum packing fraction are known for their use in the shaping of ceramic articles [2].
{"title":"Polyolefin-Based Composites by Polymerization-Filling Technique","authors":"P. Dubois, M. Alexandre, François Hindryckx, R. Jerome","doi":"10.1080/15583729808546031","DOIUrl":"https://doi.org/10.1080/15583729808546031","url":null,"abstract":"1. INTRODUCTION Dispersions of inorganic fillers within polymers are commonly designated as polymer-based composites. The properties of these materials are isotropic or anisotropic, depending on the geometry of the filler particles and the effect of the processing conditions on their orientation. Fillers are used to improve some physicomechanical properties of the polymer, the material processability, or decrease the final cost [1]. As a typical example, highly filled composites in which the filler concentration approaches the maximum packing fraction are known for their use in the shaping of ceramic articles [2].","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"22 1","pages":"511-565"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83315469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-02-01DOI: 10.1080/15321799708014735
S. Osawa, A. E. Zachariades, R. Saraf, R. Porter
Abstract From the early days of plastics, biaxial orientation has been studied as a means of changing properties [la]. Draw in two directions, rather than just one, has been widely studied with different thermoplastics (polyethylene [1–24], polypropylene [25–451, poly(ethy1ene terephthalate) [12, 46–71], and many others [72–861. The mechanical properties of tensile modulus, strength, and impact particularly of semicrystalline thermoplastics are increased by orientation. For the former, the measurement and use properties are generally in tension, and for the last, impact in the transverse direction. Optical clarity is also commonly enhanced by planar draw processes, and permeation through thickness can be changed dramatically.
{"title":"Preparation and Analysis of Planar Deformations of Thermoplastics: A Review","authors":"S. Osawa, A. E. Zachariades, R. Saraf, R. Porter","doi":"10.1080/15321799708014735","DOIUrl":"https://doi.org/10.1080/15321799708014735","url":null,"abstract":"Abstract From the early days of plastics, biaxial orientation has been studied as a means of changing properties [la]. Draw in two directions, rather than just one, has been widely studied with different thermoplastics (polyethylene [1–24], polypropylene [25–451, poly(ethy1ene terephthalate) [12, 46–71], and many others [72–861. The mechanical properties of tensile modulus, strength, and impact particularly of semicrystalline thermoplastics are increased by orientation. For the former, the measurement and use properties are generally in tension, and for the last, impact in the transverse direction. Optical clarity is also commonly enhanced by planar draw processes, and permeation through thickness can be changed dramatically.","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"42 1","pages":"149-198"},"PeriodicalIF":0.0,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86868061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-05-01DOI: 10.1080/15321799608015225
J. Gao, A. Penlidis
Abstract Several models have been proposed in the literature over the last two decades in order to simulate free-radical homopolymerizations. However, most of these models deal with one specific monomer system, usually under restricted polymerization conditions.
{"title":"A Comprehensive Simulator/Database Package for Reviewing Free-Radical Homopolymerizations","authors":"J. Gao, A. Penlidis","doi":"10.1080/15321799608015225","DOIUrl":"https://doi.org/10.1080/15321799608015225","url":null,"abstract":"Abstract Several models have been proposed in the literature over the last two decades in order to simulate free-radical homopolymerizations. However, most of these models deal with one specific monomer system, usually under restricted polymerization conditions.","PeriodicalId":16139,"journal":{"name":"Journal of Macromolecular Science-reviews in Macromolecular Chemistry and Physics","volume":"154 1","pages":"651-780"},"PeriodicalIF":0.0,"publicationDate":"1996-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81725172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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