PC辐射接枝PS及其对PC／PS共混物的增容作用

报导了用γ射线辐照聚碳酸酯（ＰＣ）和苯乙烯（Ｓｔ）混合物，通过ＩＲ谱和称量法证实ＰＣ和Ｓｔ发生了辐射接枝反应，研究了溶剂、单体浓度等因素对接枝反应的影响，得到了ＰＣ－ｇ－ＰＳ。并用ＤＳＣ和ＳＥＭ研究了ＰＣ／ＰＳ、ＰＣ／ＰＳ／ＰＣ－ｇ－ＰＳ熔融共混体系的相容性，结果表明，ＰＣ－ｇ－ＰＳ对以ＰＳ为连续相ＰＣ为分散相和ＰＣ为连续相ＰＳ为分散相的共混体系均有明显的增容作用。     

聚氯乙烯／聚丙撑碳酸酯共混相容性研究

分别用溶液法和熔融法制得聚氯乙烯（ＰＶＣ）与聚丙碳酸酯（ＰＰＣ）共混试样，用ＤＳＣ证明ＰＶＣ／ＰＰＣ不相容，但它们不相容的程度受分子量、共混比例及共混方法等因素的影响，并根据玻璃化转变温度计算出溶液２共混试样ＰＰＣ富相中ＰＶＣ的质量百分含量。用ＤＭＡ说明了ＮＢＲ／ＰＰＣ对ＰＶＣ／ＰＰＣ共混体系具有良好的增容作用，共混体系中ＰＰＣ的用量对共混体系相容性有一定程度的影响，加入适量的ＰＰＣ可提高共混试样     

PC-g-PS增容PC/PS共混体系的相容性和性能

研究了不同配比的ＰＣ／ＰＳ共混体系的物理和力学性能及其与相容性的关系,结果表明,ＰＳ含量越高,拉伸强度、冲击强度、密度和吸水率等越低,而表面硬度和耐溶剂开裂能力则提高。通过ＤＳＣ谱、ＳＥＭ等实验结果表明,少量的辐射接枝共聚物ＰＣ－ｇ－ＰＳ加入ＰＣ／ＰＳ共混体系,即能明显改善其相容性。加了共聚物以作为增容剂后,共混物的拉伸强度、冲击强度、密度、表面硬度和耐溶剂开裂能力均要比其相应的简单共混物的值来得高,而吸水率则有所下降。     

原位聚合制备高相容聚碳酸酯／聚苯乙烯体系的研究（Ⅰ）

采用原位聚合的方法能将一定比例、一定分子量的聚苯乙烯（ＰＳ）引入聚碳酸酯（ＰＣ），形成一种高相容的共混体系。分子量并不太高的ＰＳ有效地改善了ＰＣ的结构，以至有关样品的力学性能甚至高于纯ＰＣ的性能（当ＰＳ含量为１２％时，拉伸强度增加８．７％左右）。与相同组成的溶液共混方法获得的体系比较，各种表征方法均表明了原位聚合体系相容性的显著提高。原位聚合制备的ＰＣ／ＰＳ共混材料是一种全透明的、高相容的工程塑料。     

聚碳酸酯改性环氧树脂的结构与性能

采用ＤＳＣ，ＤＭＡ，ＦＴＩＲ和ＳＥＭ等方法研究了ＰＣ／Ｅ５１／ＴＥＰＡ和ＰＣ／Ｅ５１／ＤＤＳ两种共混体系的经、结构特征、力学和热性能。实验表明：体系的固化反应可按原位固化方式进行，ＰＣ对固化反应起促进作用。共混体系具有均相结构特征，两组份间存在有较强的氢键作用，从而提高了体系的Ｔｇ，模量、密度和热稳定性。ＰＣ／Ｅ５１／ＴＥＰＡ样品透明，两个体系对冲击韧均略有改善。     

PHB与PCL,PECL可生物降解高分子共混体系的研究

本文讨论了聚β－羟基丁酸酯／聚ε－己内酯（ＰＨＢ／ＰＣＬ）、聚β－羟基丁酸酯／聚ε－己内酯－聚乙二醇嵌段共聚物（ＰＨＢ／ＰＥＣＬ）共混体系的相容性、结晶性、形态结构及断裂表面形貌。ＰＨＢ／ＰＣＬ体系是不相容的，ＰＨＢ、ＰＣＬ的结晶度随共混组成而改变。ＳＥＭ结果表明，ＰＨＢ／ＰＣＬ共混膜断裂表面呈韧性断裂特征，ＰＨＢ的脆性得到改善，ＰＨＢ／ＰＥＣＬ，共混体系的相容性有所改善。     

LDPE对PBT／PC共混体系性能的影响

研究发现，在ＰＢＴ／ＰＣ共混体系中加入少量熔体指数（ＭＩ）较大的低密度聚乙烯（ＬＤＰＥ），可以改善该共混体系的加工成型性能、外观及力学性能。随着ＬＤＰＥ含量的增加，ＰＢＴ／ＰＣ巫混物的溶体指数增大；ＬＤＰＥ对共混体系还可起增韧作用，ＬＤＰＥ的加入使共混物的缺口冲击强度有明显的提高。另外，ＤＳＣ研究发现，ＬＤＰＥ的引入对共混物中ＰＢＴ组分的结晶有明显的促进作用，并使ＰＣ的玻璃化转变温度Ｔｇ下降。热失     

原位聚合制备高相容聚磷酸酯／聚苯乙烯体系的研究（Ⅰ）

采用原位聚合的方法能将一定比例、一定分子量的聚苯乙引入聚碳酸酯，形成一种高相容的共混体系。分子量并不大高的ＰＳ有效地改善了ＰＣ的结构，以至有关样品的力学性能甚至高于纯ＰＣ性能（当ＰＳ含量为１２％时，拉伸强度增加８．７％左右）。与相同组成的溶液共混方法获得的体系比较，各种表征方法的表明了原位聚合体系相容性的显著提高，原位聚合制备的ＰＣ／ＰＳ共混材料是一种全透明，高相容的工程塑料。     

聚碳酸酯/聚乙烯相容性的研究

考察了聚碳酸酯与聚乙烯（ＰＣ／ＰＥ）及聚碳酸酯与马来酸酐接枝聚乙烯（ＰＣ／ＰＥ－ｇ－ＭＡＨ）共混体系的力学性能,研究了共混体系的相容性,研究表明,ＰＥ的加入有效地提高了ＰＣ的抗冲击性能,而ＰＣ／ＰＥ－ｇ－ＭＡＨ体系的力学性能及混溶性优于ＰＣ／ＰＥ体系。红外光谱表明,接枝ＰＥ与ＰＣ共混时,发生酯交换反应,冲击断口及样条截面的扫描电镜发现,ＰＣ／ＰＥ－ｇ－ＭＡＨ的相态分布均匀,两相之间存在一定的相互作     

RPS/PE反应性共混研究

用ＩＲ、ＤＳＣ、ＧＰＣ研究了侧基含有过氧键的活性聚苯乙烯与聚乙烯之间的反频，用ＳＥＭ观察了共混物的断面形态。结果表明，ＲＰＳ／ＰＥ共混反应中生成ＰＳ－ｇ－ＰＥ，对ＰＥ／ＰＳ共混物具有增容作用，提高了共混物的力学性能。     

A study of the chemical and morphological alterations of PS and PC surfaces induced by excimer laser treatments

The effect of laser irradiation on polystyrene (PS) and bisphenol-A polycarbonate (PC) has been studied by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), optical microscopy and surface profilometry. The dependence of the surface chemical and morphological properties on wavelength and fluence has been investigated.On both materials no apparent chemical modification was induced by irradiation at 350 nm, there is no evidence of non-linear effects. Morphological alterations were induced in the PS subsurface, due to thermal shock effects. The irradiation of both polymers at 248 and 193 nm did not result in photoassisted oxidation. In the case of PS, etching is evident at 193 nm. Irradiation of PC at 248 nm induces oxygen depletion and photo-Fries rearrangements, whereas at 193 nm oxygen depletion and etching are predominant. In both polymers etching yields peculiar surface morphologies, namely the formation of debris and cone-like structures.     

High-resolution refractive index anisotropy measurement in optical fibers through phase retardation modulation

We present an improved, high-resolution method for the measurement of phase retardation induced by the material birefringence of optical fibers. Such a method can be used to retrieve information about the spatial distribution of refractive index anisotropy in the fiber by comparing the accumulated phase of a polarization component oriented along the fiber transmission axis and another located in the transverse plane. The method is based on the nonlinear regression of a phase modulated signal of known modulation amplitude altered by the sample. Experimental results obtained with our method for a standard telecommunications fiber (the Corning SMF-28) as well as photosensitive fibers (Fibercore PS1250 and PS1500) are presented with a noise-limited phase resolution below 10(-4) radians and a spatial resolution below 1 microm. An analysis of the limitation of such measurement methods is also presented including diffraction by the fibers.     

Tunable Photonic Microspheres of Comb‐Like Supramolecules

Photonic crystals (PCs) are ideal candidates for reflective color pigments with high color purity and brightness due to tunable optical stop band. Herein, the generation of PC microspheres through 3D confined supramolecular assembly of block copolymers (polystyrene‐block‐poly(2‐vinylpyridine), PS‐b‐P2VP) and small molecules (3‐n‐pentadecylphenol, PDP) in emulsion droplets is demonstrated. The intrinsic structural colors of the PC microspheres are effectively regulated by tuning hydrogen‐bonding interaction between P2VP blocks and PDP, where reflected color can be readily tuned across the whole visible spectrum range. Also, the effects of both PDP and homopolymer (hPS) on periodic structure and optical properties of the microspheres are investigated. Moreover, the spectral results of finite element method (FEM) simulation agree well with the variation of structural colors by tuning the periodicity in PC microspheres. The supramolecular microspheres with tunable intrinsic structural color can be potentially useful in the various practical applications including display, anti‐counterfeit printing and painting.     

Time-resolved studies of photoinduced birefringence in azobenzene dye-doped polymer films

We measured transient photoinduced birefringence (delta n) in various azobenzene dye films by pumping with a nanosecond pulse at 532 nm and probing at 633 nm. The switch-on times for the photoinduced birefringence range from nanoseconds to milliseconds and are systematically related with the lowest optical transition energies for those films. Moreover, our results suggest that the transient photoinduced birefringence measurement is a convenient way to determine the relative energies of pi-pi(*) and n-pi(*) states in azo-based materials.     

Two-dimensional measurement technique for birefringence vector distributions: measurement principle

The two-dimensional measurement principle for a birefringence vector distribution in transparent materials is analyzed. The system nonuniformity that results from the system components makes the two-dimensional measurement principle quite different from that of a point-measurement method, and the measurement principle requires a two-dimensional analysis. A pulsed optical phase modulation is employed to simplify the two-dimensional mathematical analysis. As a result, concepts are proposed of the system function that characterizes the system nonuniformity that results from the system components and of the intrinsic function that is related to the birefringence vector distribution in a birefringent sample. The influence of the system nonuniformity on the two-dimensional measurement is eliminated by measurement of the intrinsic function, whereas its two values allow for the mathematical separation of the birefringence vector components. The effectiveness of the two-dimensional analysis is illustrated by measurement of a birefringence vector distribution, which is induced by an internal stress distribution in a poly(methyl methacrylate) plate, owing to the photoelastic effect.     

Analysis of warpage and shrinkage properties of injection-molded micro gears polymer composites using numerical simulations assisted by the Taguchi method

Microgears containing four cavities and consisting of three different types of thermoplastic materials, namely, the amorphous polycarbonate/acrylonitrile–butadiene–styrene blend (PC/ABS), amorphous polyphenylene–ether/polystyrene (PPE/PS), and crystalline polyoxymethylene (POM) filled with glass fibers were analyzed. Molding parameters such as packing time, cooling temperature, molding and melting temperatures, packing and injection pressures, and fiberglass percentages are the most important factors affecting warpage and shrinkage. Three factors and their interactions were investigated in this case study. The effects of the injection parameters on warpage and shrinkage at different fiberglass percentages and cooling temperatures were analyzed according to the Taguchi method. The minimum values for warpage (0.0051 mm) and shrinkage (2.2886%) were derived from the PC/ABS and PPE/PS composites, respectively. Process efficiency predictions and conformational analyses of the optimal levels for each injection molding parameter were conducted to demonstrate the advantages of the Taguchi analytical method. The highest improvement percentages in the shrinkage and warpage analyses were obtained from the PPE/PS and the PC/ABS, respectively. PPE/PS was the best polymer composite by shrinkage analysis because of its molecular structure and minimum temperature at the flow front range, while the PC/ABS behaved the best in the warpage analysis.     

Variables affecting polarization-sensitive optical coherence tomography imaging examined through the modeling of birefringent phantoms

Characteristics of tissue birefringence provide valuable diagnostic information when optical coherence tomography (OCT) imaging is performed. We mathematically model single-detector polarization-sensitive (PS) OCT (PS-OCT) for imaging an alternating layered phantom with birefringence. The theoretical analysis and the simulated data all reveal complexities associated with PS-OCT imaging. Various tissue parameters affect the retrieved PS-OCT signal and hence the image features. A better understanding of the mechanisms that control PS-OCT imaging would be useful for interpretation of tissue images and ultimately useful to provide more diagnostic information.     

Contrast mechanisms in polarization-sensitive Mueller-matrix optical coherence tomography and application in burn imaging

We investigate the various contrast mechanisms provided by polarization-sensitive (PS) Mueller-matrix optical coherence tomography (OCT). Our PS multichannel Mueller-matrix OCT is the first, to our knowledge, to offer simultaneously comprehensive polarization-contrast mechanisms, including the amplitude of birefringence, the orientation of birefringence, and the diattenuation in addition to the polarization-independent intensity contrast, all of which can be extracted from the measured Jones or the equivalent Mueller matrix. Theoretical analysis shows that when diattenuation is negligible, the round-trip Jones matrix represents a linear retarder, which is the foundation of conventional PS-OCT, and can be calculated with a single incident polarization state, although the one-way Jones matrix generally represents an elliptical retarder; otherwise, two incident polarization states are needed. The experimental results obtained from rat skin samples, which conform well with the histology, show that Mueller OCT provides complementary structural and functional information on biological samples and reveal that polarization contrast is more sensitive to thermal degeneration of biological tissue than amplitude-based contrast. Thus, Mueller OCT has significant potential for application in the noninvasive assessment of burn depth.     

Structural and optical characterization of ZnO doped PC/PS blend nanocomposites

PC50%/PS50% polymer blend nanocomposites, undoped and doped with different concentration of ZnO nanoparticles (1, 2, 3 wt%), have been prepared using solution casting method. Structural and optical studies have been performed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Ultraviolet–Visible spectroscopy (UV–Vis). ZnO nanoparticles have been synthesized by chemical route method. The nanostructure of the ZnO nanoparticles has been ascertained through X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical Absorption Spectra has been used to study optical constants of prepared blend nanocomposites. Energy band gap of PC/PS – ZnO blend nanocomposites have been calculated by using Tauc relation. The band gap of the nanocomposites decreases as ZnO wt% increases. Extinction coefficient, refractive index and real & imaginary part of dielectric constants increase with increase in ZnO nanoparticles wt%.