Fourier transform infrared micro spectroscopy mapping studies of weathered PVC capstock type formulations. II: Outdoor weathering in pennsylvania

FTIR micro spectroscopy coupled with mapping techniques is a powerful methodology to evaluate dimensionally dependent changes such as those encountered in PVC weathering processes. It is based on the complexity and specificity of the infrared spctrum and the dimensional resolution of the microscope. This paper will outline a systematic FTIR study of changes observed during outdoor photo degradation of PVC siding capstock formulations, as a function of exposure time and TiO₂ level. The results are compared with previously obtained accelerated QUV data. Profiles through the thickness dimension were analyzed to identify degradation species and depth distribution.     

Applications of infrared spectroscopy to customer problems in the vinyl industry

Identifying polymers, additives and contaminants presents unique challenges. Fourier transform infrared spectroscopy (FT-IR) coupled with spectral searching techniques is a very efficient and powerful methodology to answer most identification questions. It is based on the unique IR spectrum characteristic of each compound. This paper outlines procedures employed in the identification of typical PVC formulations, starting with the resin and proceeding to impact modifier, process aids, lubricants, stabilizer system and fillers. The emphasis is on FT-IR microscopy as the most versatile approach requiring small samples and minimal to no sample preparation. Other commonly used FT-IR techniques are also outlined. Wet separation protocols, applicability and limitations as related to FT-IR analysis are discussed. Typical examples include vinyl siding, packaging and bottle formulations as well as contaminants often encountered in these formulations and raw materials.     

Preparation of hollow magnetite microspheres and their applications as drugs carriers

ABSTRACT: Hollow magnetite microspheres have been synthesized by a simple process through a template-free hydrothermal approach. Hollow microspheres were surface modified by coating with a silica nanolayer. Pristine and modified hollow microparticles were characterized by field-emission electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FT-IR and Raman spectroscopy, and VSM magnetometry. The potential application of the modified hollow magnetite microspheres as a drug carrier was evaluated by using Rhodamine B and methotrexate as model drugs. The loading and release kinetics of both molecules showed a clear pH and temperature dependent profile. GRAPHICAL ABSTRACT: Hollow magnetite microspheres have been synthesized. Load-release experiments with Rhodamine-B as a model drug and with Methotrexate (chemotherapy drug used in treating certain types of cancer) demonstrated the potential applications of these nanostructures in biomedical applications.     

Rigid PVC formulation optimization using sequential simplex

A rigid PVC formulation was optimized for processing window and cost using sequential simplex techniques in combination with desirability functions. This optimization was performed on seven of the ten ingredients from a ‘standard’ siding compound with a relatively limited number of experiments. The processing window contour mapping technique was used to evaluate the effects of formulation changes. This was combined with the formulation cost by using desirability functions to give an overall response for the simplex to optimize. The basic mechanics of sequential simplex and desirability functions are described along with the results of the optimization.     

傅立叶变换红外光谱法在纤维分析中的应用

本文综述了傅立叶变换红外光谱法在纤维分析中的应用与进展。内容涉及衰减全反射和漫反射傅立叶变换红外光谱法,傅立叶变换红外光声光谱法、显微傅立叶变换红外光谱法,傅立叶变换红外光谱仪与各种仪器的联用,以及计算机技术的应用与发展。     

Weatherability of rigid vinyl siding

Vinyl siding is described as a product in the early maturity stage of business development. The competitive position of rigid vinyl siding vis-a-vis other products is discussed. Total weathering exposures from point sources not usually thought of are reviewed. Methods of control for weathering caused changes as well as resistance evaluation are covered. The impact on the industry of the voluntary product standard PS55-72 is mentioned.     

Superior balance of weatherability and impact performance with acrylic‐capped vinyl siding

Vinyl siding, particularly in darker colors, has to be durable and be able to retain most of its original color when exposed outdoors. As the color palette for vinyl siding has been expanding and more and more colors are being offered to the homeowner, the need exists to improve color hold. A new acrylic capstock polymer, based on core‐shell technology, which can be coextruded onto vinyl siding, has been shown to provide excellent color retention, with good processability, impact and impact retention, and suitable gloss. The properties of this new capstock polymer are compared to other choices for capping vinyl siding. J. VINYL ADDIT. TECHNOL., 13:26–30, 2007. © 2007 Society of Plastics Engineers.     

A novel impact modifier system for vinyl siding and profile substrate

The use of a newly developed ABS impact modifier in coextruded vinyl siding and window profile substrate is discussed. Considerations of toughness at room and low temperature, output, reduced lubricant levels, and weatherability of the finished siding are reviewed. Actual outdoor weathering results are presented, along with long-term heat aging tests, showing the modifier to have good property retention characteristics.     

Rigid cellular PVC—the next house siding material?

The technology for extruding rigid cellular PVC has grown substantially over the past decade. Formulation additives, tooling, and processing expertise have made possible a variety of applications—relatively complex profiles, foam-core pipe, thermoformable foam sheet, and house siding. In the U.S. market, vinyl house siding is typically a relatively thin extrusion that is folded into a final shape that resembles wood cladding in appearance. An alternative to conventional form vinyl siding could be a foam structure that is thicker and stiffer than the solid form, and with a density similar to that of wood. This paper presents several performance advantages of rigid cellular PVC cladding in comparison to the current solid product, in addition to mentioning certain limitations that exist in the foam product that is produced with the technology available today.     

静电纺丝法制备BaO微/纳米纤维及其表征

以聚乙烯吡咯烷酮(PVP)为络合剂,与醋酸钡[Ba(CH3COO)2]反应制得前驱体溶液;以36%乙酸为钡盐的相容剂,和乙醇组成了混合溶剂体系,用静电纺丝法制备了PVP/Ba(CH3COO)2纤维,经煅烧得到BaO微/纳米纤维。对所制备纳米纤维的结晶度、纯度和表面形貌,分别采用差热-热重分析、红外光谱、X-射线衍射、扫描电镜等进行了表征。结果表明:煅烧前后,纤维的结晶度和形貌有很大变化。     

温度与pH敏感性大孔聚P（NIPAM-co-MAA）水凝胶的制备及性能研究

以乙醇水溶液作为反应介质,成功制备了温度与p H快速响应性聚（N-异丙基丙烯酰胺-co-甲基丙烯酸）[P（NIPAM-co-MAA）]水凝胶,研究了乙醇水溶液的浓度对凝胶性能的影响。通过红外光谱（FT-IR）﹑扫描电镜（SEM）﹑测溶胀比对凝胶性能进行了表征。结果表明,凝胶具有相同的化学组成与结构,但具有不同的微观形态;当乙醇浓度为30%-80%时,凝胶的溶胀率和退涨率随着反应介质中乙醇浓度的增加而增加。所制备的凝胶表现出较强的温度与p H敏感性以及较快的去溶胀速率。     

The effect of fluorosurfactant,copolymer latex,and cross-linker on the surface properties of floor polishes: An investigation using AFM with adhesion mapping

The performances of three fluorosurfactants of different perfluoroalkyl chain lengths in styrene-butadiene (SB) and styrene-acrylic (SA) latex formulations having different virtual cross-linkers were investigated with atomic force microscopy (AFM). Topographic mapping provided no conclusive relationship with macroscopic observations of floor polish performance (with “performance” being judged by absence of haze and uniformity of flow and leveling.) Adhesion mapping of the film surfaces revealed mesoscale lateral phase separation for the zinc cross-linked SB latex formulations with specific fluorosurfactants, but not for the SA latex formulations with either calcium or zinc cross-linking. FT-IR spectroscopy analysis supports the contention that lateral phase separation occurred due to the formation of a complex between the fluorosurfactant and the zinc cross-linking agent when used in the SB formulations. All three fluorosurfactants successfully flowed and leveled the SA formulation, using either calcium or zinc cross-linking, without the formation of a complex. These experiments present high resolution adhesion maps of latex films that link mesoscopic properties to macroscopic performance of the dried floor polish films.     

Formulations for vinyl house siding: History,present, future

In the early 1960s, vinyl house siding was first commercialized. The colors were pastels and included white, green, yellow, and gray. All siding tended to bleach and fade (oxidize) to an extent where medium and dark colors were unacceptable, since the fading is more noticeable in deeper colors. All the early siding was made from cubes on single-screw extruders. Powder compounds were first introduced in the late 1960s, as was twin-screw extrusion. At the same time higher processing temperatures were used on, both twin- and single-screw extruders. That led to a well-fused and tougher product. Formulation changes reduced bleaching and fading and permitted such medium-depth colors as tan, gold, beige, blue, and olive. This technology allowed rapid growth in the vinyl siding industry in the late 1970s. Surface distortion (oil canning) was recognized as a potential problem with the early gray color and recognized as a major problem with dark colors; it was resolved only by understanding the fundamental principles involved. Another major problem was the fading in dark colors and here again extensive research into the principles of weathering led to the use of a thin, highly weatherable capping as a cost-effective solution. For the future, many technical developments can be expected in this rapidly growing market. However, judging by the occasional withdrawal of a formulation from the market, and by an occasional homeowner complaint, present performance in several properties must be judged as just adequate. For this market to continue its rapid growth, future performance should be better than today's. This can be accomplished without hurting economics by careful understanding of all parameters involved. Formulation changes will allow better performance. Standards must be raised to control product performance, especially surface distortion and color stability in darker colors, and to insure retention of physical properties after long-term weathering.     

Thermal degradation characteristic of Tetra Pak panel boards under inert atmosphere

hermal degradation characteristics of Tetra Pak panel boards (TPPB) can be useful to improve usage of such panels as an alternative to wood-based products such as plywood, fiberboard, and particleboard. In the study, samples from the TPBBs manufactured from waste Tetra Pak packages (WTPP) were heated in a nitrogen atmosphere at different heating rates (10, 15 and 20 °C/min) using a thermal analysis system. The Coats-Redfern kinetic model was applied to calculate kinetic parameters. The degradation rate equations were then established. In addition, the kinetic compensation effect (KCE) was used to correlate the pre-exponential factor (k _o ) with activation energy (E _a ) and the existence of the KCE was accepted. TG-FT/IR analyses were applied to the TPPB degradation and then the FT-IR stack plot was used to analyze gas products (CO₂, CH₄, HCOOH, and CH₃OH). Infrared vibrational frequencies and the micro, crystal structure of the TPPBs were investigated by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and X-Ray diffraction analysis (XRD), respectively.     

相容剂对PE基木塑挂墙板性能的影响

以木粉和废HDPE为主要原料,用挤出成型的方法制备PE基木塑挂墙板,试验研究了相容剂种类、相容剂加入量对木塑挂墙板性能的影响,通过性能测试和断面SEM分析,结果表明:添加相容剂M603的木塑挂墙板性能最好;MAPE加入量增加,弯曲强度和落锤冲击高度增加,吸水率降低,MAPE加入量8%~10%比较合适。     

Volatiles released during the weathering of PVC

Volatile organic compounds and organochlorine species liberated by UV exposure of poly(vinyl chloride) (PVC) siding samples have been identified and preliminary quantification made. These volatiles included those remaining in a PVC sample after weathering or laboratory UV exposure and which could be released by thermal desorption. In addition, by using a flow-through cell and granular carbon adsorbents, volatile species directly desorbed during laboratory UV exposure were measured. Total directly desorbed organochlorine compounds were about 1/20 of the weight of hydrogen chloride as measured by conductometric analysis, Quite similar products were observed from old (～1984) and current (1995) commercial siding formulations. Observed volatile compounds are proposed to come from the TiO₂-controlled photo-oxidation of both PVC and its additives such as impact modifiers.     

Preparation, Characterization of Sulfur-Doped Nanosized TiO2 and Photocatalytic Degradation of Methylene Blue Under Visible Light

Sulfur-doped TiO₂ catalysts were prepared by a mechanochemical method. The prepared catalysts exhibited photocatalytic activity in methylene blue degradation under visible light. The catalyst structure has been characterized using UV–visible spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry analysis (TGA) as well as Fourier transform infrared spectroscopy (FT-IR). UV–visible spectroscopy revealed that the absorption edge of the doped TiO₂ was red-shifted compared with bare TiO₂. XRD patterns suggested that the brookite phase became more prevalent with increasing ball milling duration. In addition, surface sulfate species were detected by FT-IR, XPS and TGA. We deduce the rise of catalytic activity is due to the synergetic effect between the brookite phase and the anatase phase that would probably retard the electron–hole recombination. On the other hand, methylene blue was found to be N-demethylated during the irradiation thus giving rise to blue-shifting of peak at 664 nm in UV–visible spectroscopy.     

A comparison of the thermal and mechanical degradation of glassy polystyrene by Fourier transform infrared spectroscopy

The thermal and mechanical degradation of glassy polystyrene has been studied by Fourier Transform Infrared, FT-IR, spectroscopy. Using difference spectroscopy we have found that the products formed from these two modes of degradation were significantly different. This result is in contrast with other workers who found similar products for the thermal and mechanical degradation of polystyrene by mass spectroscopy. Our result suggests a reassessment of the thermal activation mechanism for mechanically-induced bond scission. We have also found that the distribution of oxidation products appears to depend upon the environment in which the polymer is mechanically degraded. Finally, we have demonstrated the utility of FT-IR spectroscopy for studying the mechanical degradation of polymers.     

Characterization of Barium Titanate Powders: Barium Carbonate Identification

A range of methods for the detection of barium carbonate contaminant in barium titanate powder has been assessed, namely: X-ray diffraction (XRD), scanning electron microscopy (SEM), with EDS-X-ray microanalysis, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), gas chromatography (GC) for analysis of carbon, and X-ray photoelectron spectroscopy (XPS). The most satisfactory procedure for the detection of the small amounts of BaCO₃ commonly present is FT-IR. Surface analyses by XPS show that the carbonate is present as a discrete phase and is not a surface film on barium titanate particles.     

A study on the characteristics of plasma polymer thin film with controlled nitrogen flow rate

Nitrogen-doped thiophene plasma polymer [N-ThioPP] thin films were deposited by radio frequency (13.56 MHz) plasma-enhanced chemical vapor deposition method. Thiophene was used as organic precursor (carbon source) with hydrogen gas as the precursor bubbler gas. Additionally, nitrogen gas [N₂] was used as nitrogen dopant. Furthermore, additional argon was used as a carrier gas. The as-grown polymerized thin films were analyzed using ellipsometry, Fourier-transform infrared [FT-IR] spectroscopy, Raman spectroscopy, and water contact angle measurement. The ellipsometry results showed the refractive index change of the N-ThioPP film. The FT-IR spectra showed that the N-ThioPP films were completely fragmented and polymerized from thiophene.