聚乙烯/聚甲基丙烯酸甲酯共混体系增容剂的合成与研究

本文利用光敏聚合反应,在聚乙烯大分子上接枝甲基丙烯酸甲酯,制备了聚乙烯（ＰＥ）接枝甲基丙烯酸甲酯（ＰＭＭＡ）的接枝共聚物,用作为聚乙烯聚甲基丙烯酸甲酯共混体系的增容剂。利用红外光谱对接枝共聚物的结构进行了表征。实验研究了接枝共聚物的接枝率及用量对共混体系性能的影响。结果表明,当接枝共聚物的接枝量为１０％左右时,增容效果最佳,增容剂的用量为共混体系聚甲基丙烯酸甲酯（ＰＭＭＡ）用量的２０％时,共混体系的力学性能最优,且增容剂对共混体系与油墨的粘结力影响较小     

聚苯乙烯- 甲基丙烯酸甲酯接枝共聚物的合成

通过氯甲基化反应在线型聚苯乙烯（ＰＳ）的苯环上定量地引入氯甲基（—ＣＨ２Ｃｌ）,合成了氯甲基化聚苯乙烯大分子引发剂ＰＳ—ＣＨ２Ｃｌ,在氯化亚铜／α,α′－联二吡啶配合物（ＣｕＣｌ／ｂｐｙ）催化下,以ＰＳ—ＣＨ２Ｃｌ引发甲基丙烯酸甲酯（ＭＭＡ）聚合,合成了聚苯乙烯－甲基丙烯酸甲酯接枝共聚物。用红外光谱和核磁共振氢谱证实了接枝共聚物的结构,测定了接枝共聚物中ＰＭＭＡ支链数目、接枝共聚物的支链长度、接枝率及接枝效率。结果表明,用这种方法制备的接枝共聚物相对分子质量分布较窄,接枝率可控,接枝效率高达９２％～９８％。     

新型聚丙烯固相接枝物增容聚丙烯／尼龙6共混物的研究

研究了聚丙烯与马来酸酐,甲基丙烯酸甲酯及第三单体的固相接枝共聚物「ＰＰ－ｇ（ＭＡＨ－ＭＭＡ－ＴＭ）」对聚丙烯／尼龙６（ＰＰ／ＰＡ６）共混物的增容作用。结果表明,新表明ＰＰ固相接枝物能有效地改善ＰＰ／ＰＡ６共混物的相容性,增加两相界面的粘合作用,显著提高共混物的力学性能,增容后体系假塑性增加,熔体粘度上升,活化能增加。     

聚丙烯熔融接枝马来酸二丁酯增容聚丙烯／尼龙6的研究

研究了聚丙烯（ＰＰ）与马来酸二丁酯（ＤＢＭ）的接枝共聚物ＰＰｇＤＢＭ对聚丙烯／尼龙６（ＰＰ／ＰＡ６）共混物的增容作用。研究表明,ＰＰｇＤＢＭ是ＰＰ／ＰＡ６共混体系的有效增容剂,由于共混过程中就地生成ＰＰｇＰＡ６,改善了共混物的相容性,增加了两相界面的粘合,使分散相粒径减小,分散更均匀,提高了共混物的力学性能。增容剂接枝率的高低对增容效果有一定影响,接枝物中残留单体不影响增容效果     

PVC／TPU／SBS—g—MMA共混体系研究

制备了ＳＢＳ－ｇ－ＭＭＡ系列接枝共聚物,并对其进行了表征。以ＳＢＳ－ｇ－ＭＭＡ作为ＰＶＣ／ＴＰＵ共混体系的增容剂,对不同配比的ＰＶＣ／ＴＰＵ／ＳＢＳ－ｇ－ＭＭＡ共混体系的物理力学性能、流变性等进行了研究。结果表明,ＳＢＳ－ｇ－ＭＭＡ接枝共聚物对ＰＶＣ／ＴＰＵ共混体系起到了明显的增容作用。     

PA1010／PP—g—ATBS／PP共混体系的形态与性能

采有向向双螺杆杆挤出机制备了不同组成的ＰＡ１０１０／ＰＰ及ＰＡ１０１０／ＰＰ－ｇ－ＡＴＢＳ／ＰＰ的共混物。采用聚丙烯接枝丙烯酰胺基甲基丙烷磺酸共聚物（ＰＰ－ｇ－ＡＴＢＳ）作为增容剂来研究对ＰＡ１０１０／ＰＰ共混体系形态与力学性能的影响，研究不同增容剂含量对ＰＡ１０１０／ＰＰ共混物的力学性能，形态结构的影响。     

PC／PE共混体系中增容剂最佳用量的确定

本文以聚碳酸酯（ＰＣ）／聚乙烯（ＰＥ）／聚乙烯蜡接技马来酸酐（ＰＥＷ－ｇ－ＭＡＨ）三元共混物为体系，研究了第三组份增容剂ＰＥＷ－ｇ－ＭＡＨ用量。共混物两相之间界面张力和共混物力学性能之间的相互关系。论证了通过测量高聚物之间界面张力来确定第三组份增容剂的最佳用量的技术途径。     

低密度聚乙烯接枝烯基双酚A醚对HDPE／PC共混体系性能的影响

本文采用烯基双酚Ａ醚接枝低密度聚乙烯（ＬＤＰＥ－ｇ－ＤＢＡＥ）作为高密度聚乙烯／聚碳酸酯（ＨＤＰＥ／ＰＣ）共混体系的增容剂,初步研究了ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系性能的影响。通过对共混物形态观察、耐热性能及力学性能测试,发现ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系有良好的增容效果;并发现了增容剂的最佳用量质量比大致为１０％,提高增容剂的接枝率更有利于改善共混物的性能。６５／３５ＨＤＰＥ／ＰＣ共混物的ＨＤＴ为９２℃,拉伸强度３０２ＭＰａ,冲击强度２９８ｋＪ／ｍ２,分别比未加增容剂时的８２℃,２７３ＭＰａ和１５５ｋＪ／ｍ２有较大提高。     

增容剂对HDPE／AS合金流变和力学性能的影响

研究了增容剂氯化聚乙烯接枝（丙烯腈／苯乙烯）共聚物对ＨＤＰＥ／ＡＳ共混体系加工流变性能和力学性能的影响。增容剂使共混体系的塑化时间减少,且随着增容剂用量的增加,共混体系的平衡扭矩和拉伸强度增大,而断裂伸长率在ＨＤＰＥ／ＡＳ／ＰＥ－Ｃ－ｇ－ＡＳ＝８０／２０／４时出现极大值;螺杆转速的增加使共混体系的平衡扭矩增大。     

尼龙1010／乙丙共聚物共混体系形态与性能研究

在过氧化二异丙苯（ＤＣＰ）的引发下，用反应挤出的方法制备了乙丙共聚物接枝甲基丙烯酸环氧丙酯（ＥＰＭ－ｇ－ＧＭＡ）。用Ｂｒａｂｅｎｄｅｒ单螺杆挤出机制备了不同组成的ＥＰＭ／尼龙１０１０及ＥＰＭ－ｇ－ＧＭＡ／尼龙－１０１０的共混物，用电子显微镜观察了不同共混组成的形态，与ＥＰＭ／尼龙１０１０共混体系相比，ＥＰＭ－ｇ－ＧＭＡ／尼龙１０１０体系中ＥＰＭ在尼龙１０１０中分散相尺寸明显降低，ＥＰＭ－ｇ－ＧＭＡ     

Impact,Thermal, and Morphological Properties of Poly(Lactic Acid)/Poly(Methyl Methacrylate)/Halloysite Nanotube Nanocomposites

Poly(lactic acid)/poly(methyl methacrylate) blends containing halloysite nanotube (2 and 5 phr) and epoxidized natural rubber (5–15 phr) were prepared by melt mixing. The impact strength of poly(lactic acid)/poly(methyl methacrylate) blend was slightly improved by the addition of halloysite nanotube. Adding epoxidized natural rubber further increased the impact strength of poly(lactic acid)/poly(methyl methacrylate)/halloysite nanotube nanocomposite. Single T_g of poly(lactic acid)/poly(methyl methacrylate) is observed and this indicates that poly(lactic acid)/poly(methyl methacrylate) blend is miscible. The addition of halloysite nanotube into poly(lactic acid)/poly(methyl methacrylate) slightly increased the T_g of the blends. The epoxidized natural rubber could encapsulate some of the halloysite nanotube and prevent the halloysite nanotube from breaking into shorter length tube during the melt shearing process.     

The melt elasticity of polymer blends: Polystyrene/poly(methyl methacrylate)

Samples of general-purpose polystyrene and poly(methyl methacrylate) were melt blended in a special mixer–extruder over the complete range of compositions from 100% polystyrene to 100% poly(methyl methacrylate). The blends were characterized for their melt rheological characteristics in a melt elasticity tester which measured their stress–strain behavior and strain recovery characteristics as a function of time. In addition, the blends were processed through a laboratory fiber spinning apparatus wherein the spinline tension was measured. Large maxima in the amount of recoverable strain, in the time for the strain recovery to finish, and in the melt tension were observed at a weight percent composition of 40% polystyrene and 60% poly(methyl methacrylate). The melt stress-strain curves showed double yield points at certain compositions. The results are discussed in terms of a model consisting of two interpenetrating continuous phases.     

Stereoregular poly(alkyl methacrylate)s: polymer-polymer and copolymer-polymer blends

Amorphous blends of isotactic and syndiotactic poly(methyl methacrylate) were found to be compatible. To evaluate the interaction between these tactic polymers, random copolymers of isotactic poly(methyl/ethyl methacrylate) were blended with syndiotactic poly(methyl methacrylate). Only the copolymers with an ethyl methacrylate content below 45% were compatible with syndiotactic poly(methyl methacrylate). Using a Flory-Huggins type treatment of copolymer mixtures, the segmental interaction parameters for poly(methyl methacrylate) with poly(ethyl methacrylate) and for isotactic with syndiotactic poly(methyl methacrylate) were calculated. The interaction parameter for the tactic poly(methyl methacrylate) pair was found to be small and negative.     

Characterization and Properties of Poly(methyl methacrylate)/Graphene,Poly(methyl methacrylate)/Graphene Oxide and Poly(methyl methacrylate)/p-Phenylenediamine-Graphene Oxide Nanocomposites

In this study, poly(methyl methacrylate)/p-phenylenediamine-graphene oxide, poly(methyl methacrylate)/graphene, and poly(methyl methacrylate)/graphene oxide nanocomposite series were prepared using simple solution blending technique. In poly(methyl methacrylate)/p-phenylenediamine-graphene oxide series, graphene oxide modified with p-phenylenediamine was used to improve its dispersion and interfacial strength with matrix. Morphology study of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide nanocomposite revealed better dispersion of p-phenylenediamine-graphene oxide flakes and gyroid patterning of poly(methyl methacrylate) over the filler surface. Due to nonconducting nature of graphene oxide, there was no significant variation in the thermal or electrical conductivity of these nanocomposites. Thermal conductivity of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide 1.5 was 1.16 W/mK, while the electrical conductivity was found to be 2.3 × 10^?3 S/cm.     

β-cyclodextrin as a Partial Replacement of Phosphorus Flame Retardant for Poly(Lactic Acid)/Poly(Methyl Methacrylate): A More Environmental Friendly Flame-Retarded Blends

β-Cyclodextrin was used together with isopropylated triaryl phosphate ester flame retardant to improve the flame resistance of poly(lactic acid)/poly(methyl methacrylate). Poly(lactic acid)/poly(methyl methacrylate)/flame-retardant blend (with and without β-cyclodextrin) was evaluated using limiting oxygen index, Underwriters Laboratories-94 vertical burning test, scanning electron microscopy, and thermogravimetric analysis (in O₂ and N₂). The addition of β-cyclodextrin was able to reduce the amount of flame retardant required for poly(lactic acid)/poly(methyl methacrylate) blends to achieve self-extinguishing properties. The poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends achieved Underwriters Laboratories-94, V-0, and limiting oxygen index value of 29.3%. A compact and wide coverage of char layer was formed on the burning surface of poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends.     

Improving the Mechanical Properties of Poly Methyl Methacrylate Nanocomposites for Dentistry Applications Reinforced with Different Nanoparticles

Properties of poly methyl methacrylate are improved using different nanoparticles for denture applications and the best combination is selected using multi-criteria decision-making methods. For these purposes, poly methyl methacrylate is melt compounded with TiO₂, SiO₂, and Al₂O₃ nanoparticles and then injection molded. The results of mechanical tests revealed that by addition of TiO₂ and SiO₂, the impact strengths of poly methyl methacrylate were increased 229 and 62%, respectively. Also, the results indicated a significant improvement in Young’s modulus and hardness. The implementation of multi-criteria decision-making methods illustrated that TiO₂ nanoparticles are the best candidate for improving the properties of poly methyl methacrylate for dental applications.     

Application of graft copolymers using macromonomer method to two-component polyurethane coatings

Graft copolymers as acrylic polyols in two-component polyurethane coatings were prepared by the free-radical copolymerization of methyl methacrylate, n-butyl methacrylate, n-butyl acrylate, acrylic acid, 2-hydroxyethyl methacrylate and poly(methyl methacrylate)-macromonomers. The poly(methyl methacrylate) macromonomer was prepared by the polymerization of methyl methacrylate in the presence of thiopropionic acid as a transfer agent followed by the reaction with glycidyl methacrylate. These polymers, whose numbers of poly(methyl methacrylate) macromonomer branches and the molecular weights of the poly(methyl methacrylate) macromonomer branches were controlled, offer an advantage over conventional resins with respect to the application/appearance of coatings as well as the final film properties. Some of these advantages were higher solids and a better control of the coating rheology, an increase in the cross-linking reactivity of the polyols with polyisocyanate and improvement in film toughness. The change in the morphological structure of the films under tensile stress was of particular interest.     

Separation of poly(methyl methacrylate)s according to their tacticity

Summary The unconventional liquid chromatography of polymers under limiting conditions of their solubility was applied to poly(methyl methacrylate)s differing in their tacticity. The polymers were dissolved in thermodynamically good solvents and injected into an appropriate size exclusion chromatographic (SEC) column flushed with matched, moderately strong nonsolvents. The set of (limiting) conditions was found under which less soluble syndiotactic poly(methyl, methacrylate) moved along the column together with the zone of its initial solvent while better soluble isotactic poly(methyl methacrylate) was eluted according to the SEC mechanism. This indicates the potential of liquid chromatography under limiting conditions to characterize the tacticity of poly(methyl methacrylate)s.     

Polyallene-based graft copolymer via 6-methyl-1,2-heptadien-4-ol and methyl methacrylate

A series of well-defined graft copolymers with a polyallene-based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of living coordination polymerization of 6-methyl-1,2-heptadien-4-ol and atom transfer radical polymerization of methyl methacrylate. We first prepared poly(alcohol) with polyallene repeating units via 6-methyl-1,2-heptadien-4-ol by living coordination polymerization initiated by [(η³-allyl)NiOCOCF₃]₂, followed by transforming the pendant hydroxyl groups into halogen-containing ATRP initiation groups. Next, grafting-from route was used for the synthesis of the well-defined graft copolymer with excellent solubility: poly(methyl methacrylate) was grafted to the backbone via ATRP of methyl methacrylate. This kind of graft copolymer is the first example of graft copolymer via allene derivative and methacrylic monomer.     

Coating silver nanoparticles on poly(methyl methacrylate) chips and spheres via ultrasound irradiation

Ultrasound irradiation is used for anchoring silver nanoparticles with an average size of ～ 51 nm onto the surface of poly(methyl methacrylate) PMMA chips (2 mm diameter), and silver nanoparticles with an average size of ～ 20 nm onto the surface of the PMMA spheres (1–10 μm). The sonochemical reduction was carried out under argon atmosphere at room temperature. The silver nanoparticles were obtained by the irradiation of a mixture containing the PMMA, silver nitrate, ethylene glycol, ethanol, water, and 24% (wt) aqueous ammonia for 2 h, yielding a PMMA‐nanosilver composite. By controlling the atmosphere and reaction conditions, we could achieve the deposition of silver nanoparticles onto the surface of poly(methyl methacrylate). The silver‐deposited PMMA chips (loaded with 0.01–1.0 weight percent silver) were successfully homogenized in melt by extrusion and then injection molded into small, disc‐shaped samples. These samples were analyzed with respect to their directional spectral optical properties in UV, VIS, and IR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007