ساختار منفذ و خصوصیات آکوستیکی دانه های کوپلیمر شبکه ای شده ماکرو منفذ دار
Abstract
The macroporous and elastomeric beads from polyurethane acrylate (PUA), ethyl methacrylate (EMA), and styrene (St) are prepared by suspension polymerization using n-heptane as porogen and 1,2-divinylbenzene (DVB) as cross-linking agent. The scanning electronic microscope results show that the beads of PUA–EMA–St cross-linked copolymers have many large pores on their surfaces and interiors, and the macroporous sizes are dependent of the copolymer composition and the dosages of cross-linking agents and porogen. Average porous diameters decrease as the dosages of DVB increase and the contents of PUA and porogen decrease. The cross-linked copolymers have two kinds of beads (one with many larger holes on the surface and another with much smaller pores or without pore), when the ratio of PUA to EMA and St is from 6/4 to 4/6. The macroporous and elastomeric beads can improve the underwater acoustic absorption properties of the polyurethane/epoxy (PU/EP) blend elastomer, and the underwater acoustic properties of the composites based on PU/EP blend elastomer and the beads depend mainly on the amounts of the beads and the dosages of porogen.
Introduction
Porous or macroporous polymer microspheres, or microparticles, or microbeads have been extensively investigated in recent years because of their numerous potential applications, including as absorbents, cosmetics, foams, drug delivery, enzyme immobilization carriers, chromatographic materials, solid-supported reagents and catalysts, damping materials, and airborne acoustic absorption materials [1–6]. They can be prepared by physical and chemical methods such as phase inversion [7], solvent evaporation [8], spray drying [9], emulsion polymerization [10–12], suspension polymerization [13–15], dispersion polymerization [16], precipitation polymerization [17, 18], and interfacial polymerization [19]. In most cases, polymers suitable for producing microspheres are usually hard or glassy ones due to the requirement of porous stabilization for mechanical resistance [20]. However, hard or glassy polymer microspheres are unfavorable to damping acoustic absorption due to their bad damping at room temperature. The ideal polymer microspheres as acoustic absorption materials should have more and larger pores and higher damping. Therefore, novel elastomeric beads with large pore size and high damping are desired for acoustic adsorption applications.
چکیده
مقدمه
آزمایش ها
مواد اصلی
آماده سازی نمونه ها
سنتز پلی یورتان اکریلات
آماده سازی دانه های کوپلیمر شبکه ای شده PUA–EMA–St
آماده سازی کامپوزیت بر پایه مخلوط الاستومری PU/EP و دانه های رزین ماکرومنفذ دار
تست مورفولوژی و ساختار منفذ
اندازه گیری خصوصیات آکوستیکی در زیر آب
بحث و نتیجه گیری
تأثیر نسبت وزنی عامل منفذ دار به مونومر کل برروی ساختار و منفذ و خصوصیات جذب آکوستیکی در زیر آب
تاثیر دوز DVB بر روی ساختار منفذ و خصوصیات جذب آکوستیکی در زیر آب
تاثیر مقدار دانه های کو پلیمری PUA- EMA-St بر روی خصوصیات جذب آکوستیک در زیر آب
نتایج
Abstract
Introduction
Experimental
Main materials
The preparation of PUA–EMA–St cross-linked copolymer beads
Preparation
The synthesis of polyurethane acrylate
The preparation of the composites based on PU/EP blend elastomers and macroporous resin beads
Characterization
Morphology and the porous structures test
Measurements of underwater acoustic properties
Results and discussion
The influence of DVB dosages on pores structures and underwater acoustic absorption properties
The influence of the mass ratios of PUA to EMA–St mixture on porous structures and underwater acoustic absorption properties
The influence of the amounts of the PUA–EMA–St copolymer beads on the underwater acoustic absorption properties
Conclusion
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