氨基蒽醌聚氨酯紫色微球的粒径调控及形貌

采用1,4-二氨基蒽醌作为发色体,与异佛尔酮二异氰酸酯反应生成紫色预聚物,与聚乙二醇600通过界面聚合法制备了氨基蒽醌紫色聚氨酯微球。考察了乳化剂种类、用量、乳化速度、发色体用量对微球粒径的影响。结果表明,与聚氧乙烯辛基苯酚醚-10、失水山梨醇单油酸酯聚氧乙烯醚(Tween80)和失水山梨糖醇单油酸酯(Span80)相比,十二烷基苯磺酸钠(SDBS)乳化剂更适合用于聚氨酯球的制备。SDBS质量分数3.5%(以油相为基准)的粒径分布最窄,微球粒径在350 nm左右。微球平均粒径随乳化速度增大而减小,在8000 r/min时粒径分布最集中。发色体在壳层体系中加入量为1 mmol时粒径分布系数最小,平均粒径500 nm。通过SEM和TEM表征,结果显示,聚氨酯微球粒径在500 nm左右,呈表面光滑的球形,内部呈空心结构。氨基蒽醌聚氨酯紫色微球印花织物颜色性能优异,且具有较高色牢度。     

明胶微球粒径影响因素的研究

本文采用乳化-凝聚法制备明胶微球,详细考察了明胶浓度、水油比、搅拌速度、乳化剂种类和浓度等条件对微球粒径、表面形貌的影响,利用扫描电子显微镜等测试手段研究了明胶微球的表面形貌,通过测量电镜照片上200个微球的直径,计算出了微球的粒径大小及分布,研究了其中的规律。     

大粒径磁性高分子微球的合成

本文研究了苯乙烯，丙烯酸等单体在磁性氧化铁的醇／水分散体系中的聚合行为。为了改善磁性氧化铁粒子与苯乙烯单体间的亲合性，加入聚乙二醇作为发散剂和稳定剂，制备出业径为３０－１０００μｍ的具有磁响应性的聚苯乙烯微球。     

分子印迹聚合物微球的粒径尺寸及分布

印迹技术是近年来发展起来的基于模拟抗体-抗原相互作用原理的新技术,广泛应用于手性物质拆分、仿生传感器、固相萃取、抗体模拟等领域。悬浮聚合法是制备分子印迹聚合物微球最常用的方法,本文就影响悬浮聚合法制备分子印迹聚合物微球粒径尺寸及分布的因素进行了探讨。     

亚微米中空微球聚合物的制备及其形貌调控

采用乳液聚合协同碱渗透溶胀法，制备了亚微米中空微球聚合物。通过SEM、TEM、DLS分别对中空微球的形貌和粒径进行表征，并考察了中空微球聚合物的遮盖性能。研究了引发剂用量对核粒径的影响，中间层和壳层聚合物配比对微球形貌结构及其遮盖性能的影响。结果表明，在核制备过程中，核的粒径随引发剂用量的增加而减小；对于平均粒径为148 nm的核，当中间层甲基丙烯酸丁酯（BMA）用量为10 wt%、甲基丙烯酸（MAA）用量为3 wt%，甲基丙烯酸甲酯（MMA）用量为87 wt%，壳层苯乙烯（St）用量为97 wt%，交联剂用量为3 wt%时，可制备平均粒径414 nm，中空率为40.6 %的聚合物微球，且微球表面较为光滑，此时中空微球聚合物具有优异遮盖性能，遮盖度达到66 %。     

亚微米中空聚合物微球的制备及其形貌调控

以甲基丙烯酸(MAA)、甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(BMA)、苯乙烯(St)、三羟甲基丙烷三丙烯酸酯(TMPTA)为原料,采用乳液聚合协同碱渗透溶胀法,制备了亚微米中空聚合物微球(HPM)。通过SEM、TEM、DLS分别对HPM的形貌和粒径进行了表征,并考察了HPM的遮盖性能。考察了引发剂用量对核粒径的影响、中间层和壳层聚合物质量比对HPM形貌结构及其遮盖性能的影响。结果表明:在核制备过程中,核的粒径随引发剂用量的增加而减小;对于平均粒径为148 nm的核,当中间层m(MAA)∶m(BMA)∶m(MMA)=3∶10∶87,壳层m(St)∶m(TMPTA)=97∶3时,可制备平均粒径414 nm、中空率为40.6%的HPM,且HPM表面较为光滑,此时HPM具有优异的遮盖性能,遮盖度达到66%。     

聚氨酯微球的制备方法及应用

介绍了聚氨酯微球的几种制备方法及其特点,包括悬浮聚合法、反相悬浮聚合法、自乳化法、分散聚合法、SPG膜乳化法;并对乙烯基聚合物和有机刚性纳米粒子改性聚氨酯微球和应用进行了概述.     

聚乳酸-聚氨酯微球的合成及其形态的研究

以低相对分子质量生物可降解D，L-聚乳酸(D，L-PLA)二醇和六亚甲基二异氰酸酯(HDI)为原料、1，4-丁二醇(BD)为扩链剂及聚乙烯基吡咯烷酮(PVP)为悬浮剂，通过悬浮聚合法初步合成了一种新型聚氨酯微球(PUMS)。用扫描电子显微镜(SEM)考察了BD的含量对微球表面形态的影响，通过激光粒度分析仪讨论了搅拌速率和PVP浓度对微球粒径及其分布的影响，用傅立叶变换红外光谱(FTIR)粒度分析仪对微球的化学结构进行了表征。结果表明，合成的微球的平均粒径随搅拌速率和PVP浓度的增加而减少，粒径分布变宽；当搅拌速率为400r／min，PVP质量分数为1．5％时。微球的平均粒径约47μm，粒径分布最窄。约在10～90μm；微球表面有孔，但随着BD含量的增加，微球表面变得相对粗糙，孔数减少，孔径减小，直至孔消失。     

聚氨酯分散体粒径及粒径分布与粒径控制

介绍了聚氨酯分散体粒径与粒径分布概念、测定粒径的方法,分析探讨了分散体内在因素和外部因素对粒径的影响以及聚氨酯分散体的粒径控制。     

聚氨酯彩色聚合物微球的研究

本文对聚氨酯彩色聚合物微球的配方、合成工艺进行探索,并对各种影响因素进行了研究,寻找到较为合理的工艺路线。     

Particle size analysis by transmission fluctuation spectrometry with band-pass filters

The transmission fluctuation spectrometry (TFS) is a recently-developed method for real-time, online/inline particle analysis in two-phase flows, whereby the particle size distribution (PSD) and particle concentration can be measured simultaneously. This study presents a new technique of data processing to the fluctuating transmission signal. Instead of low-pass filters, band-pass filters are employed to improve the resolution of the measurement on particle size distribution. Based on the layer model, an analytical expression of the spectrum of the fluctuating transmission through a monolayer is derived and hence the spectrum of the fluctuating transmission through a 3-dimensional suspension is formulated. The comparison between simulation and theory at low concentrations shows a satisfactory match. Measurements on a mono-modal suspension are presented. It is found that the measurements using band-pass filters are of better resolution in the PSD than those with low-pass filters.     

Particle size separation by alternating electrophoretic deposition

This paper describes a study of the size distribution of the particles deposited under different frequencies by alternating electrophoretic deposition. A low concentration suspension of SnO₂ particles was prepared in acetone and particles of SnO₂ were deposited on electrodes by the low frequency alternating electrophoretic deposition method. Scanning electron microscopy (SEM) showed that increasing the frequency from 0 to 1000 Hz reduces the average size of the SnO₂ particles deposited. Particle size distributions obtained from the SEM images show the sizing capability of the alternating electrophoretic deposition method.     

Particle size design of digitoxin in supercritical fluids

Bioavailability of the pharmaceutical substances is very important for their activity. In case of necessity, bioavailability can be improved by reducing the particle size of the drugs. In this study, particle size of digitoxin was reduced by the Rapid Expansion of Supercritical Solutions (RESS). The effects of pre-expansion temperature (90-110 °C), flow rate (2.5-7.5 ml/min), spray distance (3-7 cm) on the size and size distribution of the precipitated digitoxin particles were carried out. The particles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and LC-MS analysis.While the particle size range of the original digitoxin was 0.2-8 μm, it was decreased to 68-458 nm and determined that 97% of the particles were below 200 nm depending on the different experimental conditions.Response surface method (RSM) was used to optimize the process parameters. The flow rate, 7 ml/min; spray distance, 7 cm; pre-expansion temperature, 95 °C were found to be the optimum conditions to achieve the minimum particle size of digitoxin.     

Understanding the influence of hydrogen bonding and diisocyanate symmetry on the morphology and properties of segmented polyurethanes and polyureas: Computational and experimental study

Quantum mechanical calculations (QMC) and dissipative particle dynamics (DPD) simulations were utilized to understand the nature of the short and long-range hydrogen bonding and its influence on the microphase morphology in segmented polyurethanes and segmented polyureas prepared without chain extenders through the stoichiometric reactions of hydroxy or amine terminated poly(tetramethylene oxide) (PTMO-1000) with 1,4-phenylene diisocyanate (PPDI) and 1,3-phenylene diisocyanate (MPDI). The possibility of long-range connectivity due to a network of well-ordered hydrogen bonds between symmetrical PPDI and kinked MPDI based model urethane and urea compounds were also investigated. Special emphasis was given on the understanding of the influence of diisocyanate symmetry and nature of the hydrogen bonding between hard segments on the morphology development. QMC results obtained clearly indicated the possibility of long-range ordering of hydrogen bonds between PPDI based urethane and urea groups, while MPDI based systems did not display such a behavior. DPD results strongly supported the QMC studies and clearly demonstrated the possibility of long-range connectivity of hydrogen bonds between urethane and urea groups in PPDI based segmented copolymers, leading to the formation of microphase separated morphologies in these systems, which was not observed in the kinked MPDI based segmented urethane and urea copolymers. Computational results obtained strongly supported the experimental observations reported on the morphology and thermal and mechanical properties of these segmented polyurethanes and polyureas based on PPDI and MPDI.     

FTIR investigation of the influence of diisocyanate symmetry on the morphology development in model segmented polyurethanes

Novel segmented polyurethanes with hard segments based on a single diisocyanate molecule with no chain extenders were prepared by the stoichiometric reactions of poly(tetramethylene oxide)glycol (M_n=1000 g/mol) (PTMO-1000) and 1,4-phenylene diisocyanate (PPDI), trans-1,4-cyclohexyl diisocyanate (CHDI), bis(4-isocyanatocyclohexyl)methane (HMDI) and bis(4-isocyanatophenyl)methane (MDI). Time dependent microphase separation and morphology development in these polyurethanes were studied at room temperature using transmission FTIR spectroscopy. Solvent cast films on KBr discs were annealed at 100 °C for 15 s and microphase separation due to self organization of urethane hard segments was followed by FTIR spectroscopy, monitoring the change in the relative intensities of free and hydrogen-bonded carbonyl (CO) peaks. Depending on the structure of the diisocyanate used, while the intensity of free CO peaks around 1720-1730 cm⁻¹ decreased, the intensity of H-bonded CO peaks around 1670-1690 cm⁻¹, which were not present in the original samples, increased with time and reached saturation in periods ranging up to 5 days. Structure of the diisocyanate had a dramatic effect on the kinetics of the process and the amount of hard segment phase separation. While PPDI and CHDI based polyurethanes showed self-organization and formation of well ordered hard segments, interestingly no change in the carbonyl region or no phase separation was observed for MDI and HMDI based polyurethanes. Quantitative information regarding the relative amounts of non-hydrogen bonded, loosely hydrogen bonded and strongly hydrogen bonded and ordered urethane hard segments were obtained by the deconvolution of CO region and analysis of the relative absorbances in CO region.     

乙氧基镁催化剂粉末粒度及粒度分布测定的研究

用乙醇做分散介质,用激光粒度测定仪测定四个乙氧基镁催化剂粉末试样的粒度及粒度分布,测试快速、准确。试验结果显示乙氧基镁（德国）催化剂粉末粒度最小,粒度分布集中,在四个样品中质量最好,试验结果令人满意。     

A 2-dimensional small-angle X-ray scattering study of the microphase-separated morphology exhibited by thermoplastic polyurethanes and its response to deformation

The morphological behaviour of poly(ether-urethane)s undergoing deformation was studied using two-dimensional small-angle X-ray scattering (2D-SAXS). The data was analysed using the Zernike-Prins and Percus-Yevick models, which fitted the data well and indicated morphologies composed of discrete, elongated hard segment (HS) microdomains. Although the formulations contained relatively large HS weight fractions, relatively low volume fractions of scattering bodies were indicated, which implied limited segmental de-mixing. Possible explanations for this were discussed.Curve-fitting the 2D-SAXS data for deformation experiments using the Zernike-Prins model, indicated that HS microdomains initially became aligned with the applied strain and subsequently fragmented. This suggested a morphological basis for the observed mechanical properties of these materials, which will be explored in more detail, in subsequent publications.     

Online Particle Size Measurement in Microgel Particle Suspensions: Principles and Data Analysis

If a gelled system is subjected to shearing or the concentration of reactive components is low, microgel particles are formed. Since labile microgel particles with high water capacities can often be found in food systems, and as they are important for the textural properties, particle size measurement is relevant for fundamental research and control of industrial processes. A chord length measurement system was tested for online particle sizing.     

Particle size dependence of the elastic modulus of particulate filled PMMA near its Tg

Models for composition dependence of elastic modulus of particulate filled polymers inherently assume modulus of the matrix independent of particle content and size. In this letter, experimental evidence is presented for existence of a critical particle size below which elastic modulus of the matrix becomes strongly dependent on the particle content due to the extensive chain stiffening. It is also suggested that below the critical particle size, specific interface area should replace volume fraction as the structural variable.