bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergency stopper for VCM suspension polymerization
Authors: Malmonge S. M. , Santos L. R.
Published: April 2004

Because of the exothermicity of reaction and the necessity of using active initiators for the vinyl chloride monomer (VCM) suspension polymerization reaction, a study was undertaken in order to choose the best polymerization inhibitor for emergency situations such as temperature runaway, power failures, and agitation system problems. The effect of triethylene glycol‐bis3(3 terc‐butyl‐4‐hydroxy‐5‐methyl phenyl) propionate (1) and N‐nitrosophenylhydroxylamine ammonium salt (2) cited in the literature as free radical polymerization inhibitors on VCM suspension polymerization reactions is shown.
Injection molding higher performance reinforced plastic composites
Authors: Rosato D. V.
Published: April 2004

Conventional screw plasticizing injection molding machines (IMM) have been used to mold over 50 wt% of all reinforced plastics (RP) composite processed (1–9). Principal reinforcement used is E‐glass of short glass fibers (SGF) with thermoplastics (TP) such as nylon (PA) and polypropylene (PP) (each over 25 wt% of total). Fiber lengths are usually limited to being milled to 1 mm (0.04 in); average length in molded parts are 0.3 mm (0.01 in) to 0.5mm (0.02 in); Long glass fibers (LGF) would be more desirable in obtaining better performances such as higher strength, stiffness, creep resistance, fatigue resistance and improvements in dimensional stability and thermal properties. However, fibers will degrade in length during conventional molding resulting in less efficient use of reinforcements. LGFs can start at 10 mm (0.4 in) and after IM can be in the order of at least 5 mm (0.2 in); longer fibers are also used. Special fiber impregnation techniques will permit successfully molding LGFs (1–21).
Polyolefin formulation validation using infrared spectrometric classification techniques
Authors: Van Every K. W. , Elder M. J.
Published: April 2004

Discriminant analysis using principal components of mid‐infrared spectral data is demonstrated as a powerful quality validation tool to augment sophisticated manufacturing processes where rigorous multicomponent analysis is not only costly but in many cases unwarranted. In order to balance competing requirements of validation, a multiple model approach is taken, which combines the best information available about the process, the chemistry and the spectroscopy of the formulation. A systematic approach to evaluate training data is discussed as a crucial step to insuring a diverse but homogenous calibration.
The effects of EPM long chain branching on TPO properties
Authors: Brignac Stephen D. , Young Harold W.
Published: April 2004

In this paper the effects of EPM long chain branching are examined in terms of reheological, processing, and physical property responses in mechanically blended TPOs. Morphological effects induced by this polymer variable as indicated by SEM are detailed as well. The EPMs used in this study were produced by DSM Copolymer, Inc., in Baton Rouge, Louisiana.
Effects of fillers on permeability and mechanical properties of HDPE blown films
Authors: Gill T. S. , Xanthos M.
Published: April 2004

HDPE compounds containing various amounts of rigid (platy talc) or deformable (nylon‐6) oxygen barrier components were blended in a twin‐screw extruder and processed into thin films by blown film extrusion. The films were tested for oxygen permeability and mechanical properties and analyzed for morphology. Optimization of barrier component content is shown to depend on the desired permeability level, film ductility and processability.
Compatibilizer system for extruded polyethylene foam and film
Authors: Lee Shau‐Tarng
Published: April 2004

This paper discusses the processing/product benefits of adding additives to extruded polyethylene (PE) foam and film. Low‐density polyethylene foam (over 30 times expansion) requires adequate cooling to stabilize the melt/gas system for optimal foaming efficiency. The presence of a small portion of high melting polyethylenes (i.e. LLDPE, HDPE) causes flow instability after cooling, resulting in surface defects in finished products. We found that the addition of metal oxide and fatty acid ester improved processing latitude and foam product quality. This formula was also tested in film processes at various ratios of LD/LLD/HD with promising results. It appears that this formula can allow us to accommodate post consumer resin (PCR) and to take advantage of PE price variations.
Cellulose acetate structural foam
Authors: Deanin Rudolph D. , Bernier Timothy J.
Published: April 2004

Structural foams of cellulose acetate were prepared at densities down to 1.01. Decreasing density produced decreasing cell size, decreasing flexural modulus, and surprisingly, increasing impact strength.
Recent research advances in the chemistry of poly(vinyl chloride)
Authors: Starnes William H.
Published: April 2004

Summarized briefly here are some new observations that relate to the polymerization chemistry of vinyl chloride (VC) and to the thermal degradation, thermal stabilization, fire retardance, and smoke suppression of poly(vinyl chloride) (PVC). During polymerization, head‐to‐head VC emplacement leads to β‐chloroalkyl radicals that can transfer chlorine atoms directly to VC. Another mechanism for transfer to monomer is responsible, however, for the polymer molecular‐weight reductions that occur at high VC conversions. This transfer process involves the abstraction of methylene hydrogen from the polymer by an ordinary macroradical and the subsequent bimolecular donation of a chlorine atom to VC. The propagation steps of the polymerization do not become diffusion‐controlled at VC conversions near 90%, and hydrogen abstraction from the polymer by ordinary macroradicals leads to the structural defects that cause thermal instability. The thermal dehydrochlorination of PVC involves ion pairs or four‐center concerted transition states that are highly polarized. Reversible thermal stabilization of the polymer by organic metal salts occurs by the Frye‐Horst process, and the reductive coupling of PVC chains may suppress both smoke and flame. This coupling can result from reactions of the polymer with zero‐ or low‐valent transition‐metal species that are formed in situ from appropriate additives.
Poly(vinyl chloride) polymerization performance‐enhancing initiators with emphasis on high activity grades and water‐based dispersions
Authors: Zimmermann Heinz
Published: April 2004

Vinyl chloride is most commonly polymerized by suspension processes, where surface active materials as granulating agents and organic peroxides as free radical initiators are the crucial additives, which may affect PVC qualities substantially. Among the wide variety of usable and commercially available organic peroxides, the most suitable types for an individual process need to be selected with specific regard to reactivity, polymerization performance, storage, and handling. Currently, high activity types are subject of continuously growing interest to many PVC manufacturers who are trying to achieve higher productivity and to expand their product range mainly by focusing on PVC grades of higher molecular mass. A short comparison between the different alternatives of highly active initiators is given, showing the potential for further improvement by using a new difunctional peroxyneodecanoate. Among the manifold formulations of organic peroxides, which have been developed, particular importance is attached to water‐based grades. Dispersions of solid peroxydicarbonates are explained in detail, and their outstanding benefits on performance and safety are covered.
Foamed rigid vinyl for building products
Authors: Schipper Peggy S. , Black Janine , Dymek Tony
Published: April 2004

PVC foamed building products have seen good growth lately because of their favorable properties and economics. Continued good growth is seen for the future. Expanding application areas, especially in the U.S. market, have created a need for knowledge on formulation and processin prarameters. Application areas are explored as well as raw material considerations, processing methods and parameters, and final physical properties.
An alternative to DEHP plasticized polyvinyl chloride in chemotherapy drug delivery systems
Authors: Czuba Len , Puryear Harry , Sarkar Kamal
Published: April 2004

Medical plastic selection has recently been challenged with the development and approval of a new chemotherapy drug that, because of the carrier solution used, causes extraction of di‐2‐ethylhexyl phthalate (DEHP) plasticizer from commonly used polyvinyl chloride (PVC). There is much discussion as to whether or not this extraction is a problem. However, in an effort to comply with the recommendations of the drug manufacturer, many device companies are in the process of converting their devices from DEHP plasticized tubing to tubing made with non‐phthalate plasticizer. This paper describes the effort made to both understand and comply with the recommendations made by the drug manufacturer. The testing confirms effective reduction of the phthalate plasticizer extraction.
A study of the synergism of poly(vinyl chloride)/polyether‐ester blends
Authors: Ellis Candace L. , Barry Carol M. F.
Published: April 2004

The synergism between blends of poly(vinyl chloride), PVC, and a polyether‐ester elastomer, COPE, was investigated. Previous research indicated that blends of these two polymers produced synergistic results in the melt index and Izod impact properties of the system. This research confirmed the increased flow properties of the blends using melt index, capillary rheometer, and dynamic mechanical analysis. The synergism was found to be shear rate dependent and an additive relationship was approached at high shear rates. Differential scanning calorimetry showed that the blends were immiscible. This suggested that phase separation was the cause of the synergism in the flow properties and that elongation of the COPE domains most likely produced the shear rate dependency of the blend synergism. The phase separation would also have produced the improvement in the Izod impact properties of the blends.
Extrusion of polypropylene foams with hydrocerol and isopentane
Authors: Behravesh Amir H. , Park Chul B. , Cheung Lewis K. , Venter Ronald D.
Published: April 2004

An experimental investigation was conducted to research the cell nucleation behavior in the extrusion foam processing of polypropylene (PP) using hydrocerol and isopentane. While the hydrocerol and isopentane are considered to function as the nucleating agent which determines the cell‐population density and as the blowing agent to control the volume expansion ratio respectively, both agents affected the cell‐population density. In addition, synergistic effects of these agents on the cell density were observed. In foam processing with hydrocerol, a higher cell‐population density was noted at lower processing pressures and at higher polymer flow rates. This phenomenon is of interest since the cell density, in general, increases as the processing pressure increases when only a physical blowing agent is used in the foam processing. The experimental results indicate that the nucleation in the foam processing with hydrocerol is governed by a heterogeneous nucleation mechanism; also, the quality of the mixing of the polymer and the agents, as well as the amount of gas lost during the plastication of the pellets in the barrel, exerts a strong influence on the resulting cell density.
Dynamic mechanical properties of lightly sulfonated polystryrene ionomers
Authors: Calhoun Bret H. , Moore Robert B.
Published: April 2004

The effects of counterion type and addition of plasticizers on the dynamic mechanical properties of sulfonated atactic polystyrene (SaPS) containing 2.1 mole percent ionic groups have been investigated. For SaPS neutralized with alkali metal counterions at temperatures below 180°C, the matrix Tg and elastic modulus were not significantly affected by counterion type. However, above 180°C, the breadth of the rubbery plateau significantly decreased with increasing counterion size. Neutralization of SaPS with alkyl ammonium counterions decreased both the matrix Tg and the breadth of the rubbery plateau with increasing counterion size. By incorporating an ionic plasticizer in Na+ neutralized SaPS, dynamic mechanical properties were observed to be intermediate of systems neutralized with the alkali metal and alkyl ammonium counterions.
Thermal stimulated current study of core‐shell impact modifier/PVC blends
Authors: Li Kuo‐Chen , Tang Kuo‐Chang , Lee Juh‐Shyong , Chao Cheng‐Lung , Chang Ren‐Kuen
Published: April 2004

This study examines the efficacy of core‐shell structure impact modifers, having different particle sizes and core/shell compositions, for modifying PVC's impact strength. The core and the shell's main compositions are polybutyl acrylate and polymethyl methacrylate, respectively. Also, the TSC is used to obtain the fundamental states of the blended impact modifier/PVC systems, thereby allowing them to be correlated to the above observed efficacy. Results of this study can provide valuable information toward exploring the feasibility of using the TSC data as a product development guide for designing PVC impact modifiers.
Successful extrusion of small diameter CPVC pipe
Authors: Grohman Martin , Holloway Scott
Published: April 2004

Chlorinated polyvinylchloride (CPVC) pipe is a rapidly growing market, especially 25.4 mm (1″) pipe and smaller. Extrusion of CPVC pipe presents a greater challenge than PVC, because CPVC has less heat stability and higher viscosity. However, CPVC has good physical properties, particularly with respect to heat, and can be used to make hot water pipe. This paper discusses some of the basic factors involved in screw and pipe head design for CPVC extrusion, and gives some examples of successful applications.
The effect of zinc borate in combination with ammonium octamolybdate or zinc stannate on smoke suppression in flexible PVC
Authors: Ferm Donald J. , Shen Kelvin K.
Published: April 2004

The effect of combinations of zinc borate with ammonium octamolybdate or zinc stannate on smoke suppression upon combustion of flexible PVC was studied. Effects on Oxygen Index and on residual char after ten minutes at 560°C were also evaluated. These studies were done using both a conventional dioctyl phthalate (DOP) plasticizer and a mixed plasticizer consisting of a 1:1 combination of DOP and an alkyl aryl phosphate ester. For both plsticizer systems, results showed that combinations of the zinc borate with either ammonium octamolybdate or zinc stannate gave an improved effect with respect to smoke reduction upon combustion. Thermogravimetric analysis (TGA) of PVC containing these additives showed no indication of interactions to explain this effect. TGA analyses indicated that PVC samples made with the mixed plasticizer had final decompositon temperatures which were slightly higher than those made with DOP as the plasticizer.
Photolysis of dialkyl phthalates and poly(vinyl chloride) plasticized with dialkyl phthalates at wavelengths exceeding 290 nm
Authors: Balabanovich A. I. , Denizligil S. , Schnabel W.
Published: April 2004

When dialkyl phthalate plasticizers, neat poly(vinyl chloride), PVC, and PVC plasticized with dialkyl phthalate are subjected to near UV radiation at λinc > 290 nm, chemical alterations are induced by traces of impurities capable of absorbing light in this wavelength range. The main photoproducts formed in the case of neat phthalates are olefins, alcohols, and phthalic acid anhydride. Neat PVC undergoes CCl bond cleavage and, in addition, carbonyl and polyene groups are formed. The formation of carbonyl groups is a nonlinear (auto‐accelerated) process whereas polyene generation occurs linearly with increasing irradiation time. The photolysis of phthalate‐plasticized PVC is characterized by the decomposition of the plasticizer, evidenced by the decrease in the absorption band at 278 nm, and by the formation of carbonyl groups attached to PVC and the cleavage of CCl bonds as evidenced by the increase or decrease in the IR absorption bands at about 1710 and 617/639 cm−1, respectively. Phthalates hardly influence the incorporation of carbonyl groups into PVC (an auto‐accelerated process) and retard only slightly the cleavage of CCl bonds. By contrast, phthalates sensitize the incorporation of carbonyl groups upon irradiation at λinc = 254 nm. Within the error limit no effect of the chemical nature of the phthalate on the formation of photoproducts was detectable upon performing irradiations at λinc > 290 nm.
The properties of glass fibers recycled from the thermal processing of scrap thermoset composites
Authors: Kennerley J. R. , Fenwick N. J. , Pickering S. J. , Rudd C. D.
Published: April 2004

Glass fiber reinforced composites can be recycled by combustion of the polymer in a fluidized bed and reclamation of the reinforcement. The effect of heat on the reinforcing properties of glass fibers was studied by measuring the strength of a composite incorporating heat cleaned glass cloth. This work was then extended by measuring the tensile strength of single fibers. An initial study of the residual strength of fibers processed in a fluidized bed was also undertaken by measuring the tensile strength of fibers recovered at two temperatures. It is concluded that low bed temperatures and short bed residence times are required to maximize the strength of the recovered fibers.
Determining migration of GMS antistat in polypropylene
Authors: Barnes Paul
Published: April 2004

Glycerol esters are widely accepted additives for polyolefin antistat applications. The effects of use level, fatty acid source, and monoglyceride content on antistat functionality are examined in polypropylene using electrostatic decay and FTIR analysis.
A new phosphite offers an excellent balance of properties
Authors: Avakian Roger , Gardner Pamela
Published: April 2004

Phosphites are a critical component of stabilizer formulations and provide molecular weight and color protection to the polymer. This paper profiles a new phosphite antioxidant whose structure provides an excellent balance of high activity, hydrocarbon solubility, and excellent handling characteristics. A wide range of performance data is illustrated in polypropylene.
Mechanical properties and impact toughness of talc‐filled β‐crystalline phase polypropylene composites
Authors: Tjong S. C. , Li R. K. Y.
Published: April 2004

Injection molded β‐crystalline phase polypropylene (PP) composites containing 5, 10, 20, 30 and 40% (by weight) of talc filler were studied by X‐ray diffraction, scanning electron microscopy, static tensile and falling drop weight impact tests. The X‐ray diffraction analysis showed that the talc filler suppresses the formation of β‐form PP dramatically. As a result, the β‐PP composites containing talc content ≥20 wt% consisted mainly of the α‐form PP phase. The tensile test showed that the addition of talc filler up to 40 wt% leads to an increase in Young's modulus whereas little effect is observed on the yield strength of composites with the addition of talc up to 30%. This behavior can be attributed to the load bearing effect of talc particles with a platelike structure and to good interfacial bonding exists between the matrix and filler. The impact tests revealed that the critical stain energy release rate (Gc) of the β‐PP polymers appears to increase initially with the addition of 5 wt% talc; thereafter it decreases significantly with increasing talc content.
Study of additive compatibility with poly (vinyl chloride). 1: Dynamic mechanical analysis (DMA) of impact modified rigid PVC containing ester lubricants
Authors: Bacaloglu Radu , Hegranes Barbara , Fisch Michael
Published: April 2004

The glass transition temperatures of impact modified PVC with different amounts of lubricants have been used to define two new parameters of lubrication: the saturation concentration and the efficiency constant. The use of lubricants at significantly lower concentration than the saturation concentration ensures their permanence in the polymer. They then act as internal lubricants reducing the viscosity of the melt. The use of lubricants at much higher concentrations ensures their release at the surface of the polymer, giving them an external character. The efficiency constant characterizes the capability of the lubricant to modify the properties of the polymer and increase flow. Polyacrylate impact modifiers form distinct polymer phases and consequently the effect of lubricants on impact modifier may be characterized in the same way by the two constants. The choice of impact modifier and lubricant for a given application can be rationally made by using the two characteristic parameters. The described procedure can be applied to any polymer and all the additives that can migrate in the polymeric phase as long as their glass transition temperatures can be measured.
A review of vinyl technology
Authors: Summers James W.
Published: April 2004

This is a review of PVC technology from chlorine and ethyle, to PVC polymerization, to melt processing, to properties, to recycling and environmental concerns. It is written in terms for understanding by even non‐scientists in the industry.

PVC has a large sales volume, second only to polyethylene. Its high chlorine content provides it with a very high level of combustion resistance for building products, electrical enclosures, and wire & cable insulation. PVC has a unique ability to be compounded with a wide variety of additives, making it possible to produce materials in a range from flexible elastomers to rigid compounds, materials that are weatherable such as for siding and windows, compounds that have stiff melts and little elastic recovery for outstanding dimensional control useful in profile extrusion, or low viscosity melts, which compete effectively with ABS and PC/ABS in thin walled injection molding parts such as computer monitor housings.

Some of PVC's properties are attributed to unique structures. The polymer precipitates from its monomer and grows into primary particles, which are later the melt flow units. Fusion into larger structures and product strength are controlled by break‐down of the grains into primary particles, by the choice of additives, by the amount of melting (temperature), and by the number of tie molecules (molecular weight).

The main type of polymerization is the suspension process, with significant polymerization made by the mass process and emulsion process. In the suspension process, the polymerization takes place in droplets of monomer suspended in a water.

PVC is environmentally sound. With over 50% chlorine content, chlorine makes PVC one of the most energy efficient polymers, makes PVC inherently flame retardant, and acts as a marker, enabling automated equipment to sort PVC containers from other plastics in the waste stream. Analysis from 155 large‐scale, commercial incinerator facilities found no relationship between the chlorine content of waste nor the addition of PVC, and dioxin emissions from combustion processes. New requirements from the U.S. EPA make scrubbers mandatory on all incinerators and are necessary whether or not PVC is present in the waste feed.
Pimelic acid‐based nucleating agents for hexagonal crystalline polypropylene
Authors: Li J. X. , Cheung W. L.
Published: April 2004

Isotactic polypropylene (PP) resin was doped with pimelic acid, sodium pimelate, and calcium pimelate to stimulate the growth of hexagonal crystalline polypropylene (β‐PP). The doped resin was crystallized in a differential scanning calorimeter (DSC) and during compression molding and injection molding. The effect of the additives on the formation of β‐PP was examined using DSC and wide angle X‐ray scattering (WAXS). Pimelic acid alone was found ineffective while the pimelates induced 64% to 90% of β‐growth depending on the nucleating agent system and crystallization condition. In particular, the pimelic acid/calcium stearate system produced a more consistent and higher yield of β‐PP. This was attributed to finer particle size and better dispersion of the nucleating agent.
The effects of cobalt promoter and glass fibers on the curing behavior of unsaturated polyester resin
Authors: Yousefi A. , Lafleur P. G. , Gauvin R.
Published: April 2004

In this study, a phenomenological autocatalytic kinetic model is used to describe the cure of a polyester system containing a cobalt‐based promoter. The effect of including the promoter in the cure system is discussed regarding the changes in the kinetic parameters. It was found that the cure characteristics of the unsaturated polyester system were affected by the presence of the promoter. This effect resulted in a temperature dependency of the reaction exponents as well as in a significant increase of the Arrhenius frequency factor at low temperatures. The changes in cure characteristics of promoted polyester system caused by incorporation of chopped glass fibers were also investigated. The results indicate that unlike the promoter, the presence of glass fibers does not appreciably affect the reaction exponents. However, the presence of glass fibers results in some changes in the overall reaction rate of the cure system. To take into account the unrecorded extent of reaction at high cure temperatures, a new procedure was implemented. This procedure estimates a correction factor related to the total isothermal heat of cure obtained from DSC experiments at different isothermal cure temperatures.
Developments in weatherable copolyester sheeting
Authors: Fagerburg D. R. , Donelson M. E.
Published: April 2004

Until recently, polyesters and copolyesters were not able to be seriously considered for use in an outdoor environment owing to rapid coloration upon exposure coupled with rapid loss of impact properties. Recent work at Eastman has resulted in a coextrusion technology with a high level of UV absorber that has now circumvented both of these problems. A caution on the use of accelerated device exposures will be discussed. Outdoor exposures in Florida, Arizona, and other locations will be presented and compared to the accelerated device exposures and each other. Some of the potential uses of this new technology will also be discussed.
Fourier transform infrared micro spectroscopy mapping. Applications to the vinyl siding industry
Authors: Garcia Dana , Black Janine
Published: April 2004

Fourier transform infrared (FT‐IR) micro spectroscopy is a powerful analytical technique capable of yielding high quality information with a spatial resolution as low as 10 microns. When coupled with an automated mapping stage it can offer unique evaluation capabilities. This paper describes a number of applications of FT‐IR micro spectroscopy mapping to the vinyl siding industry. Examples will focus on determining, in single sample mapping experiments, the compositional changes associated with capstock to substrate transition and evaluating the degradation species and level observed during weathering exposure throughout the thickness of the siding panel.
Functional copolymers of dibromostyrene as flame retardants for thermoplastic polyamides and polyesters
Authors: Fielding William R. , Elliott Jennifer L.
Published: April 2004

As resin requirements and environmental concerns have increased, the development of polymeric flame retardants has occurred. Brominated polystyrenes are widely used as flame retardants for thermoplastic polyesters and polyamides. The incorporation of comonomers at low levels has improved the compatibility of polybromostyrenes with each of these resin systems as evidenced by scanning electron micrographs. The improvement in physical properties and the reductionin flammability of PBT and polyamides as a function of the comonomer type and concentration are explored in this paper.
Evaluation of process aids for controlling surface roughness of extruded LLDPE
Authors: Hauenstein Dale E. , Cimbalik David J. , Pape Peter G.
Published: April 2004

A method utilizing a single‐screw extrusion tape line, where each sample of tape was analyzed off‐line with a surface roughness tester, was used to screen the effectiveness of process aids in controlling the surface roughness characteristics of extruded LLDPE. The effectiveness of commercial process aids and new silicone process aid candidates was evaluated and compared as a function of addition level, mode of addition, as well as extrusion rate. A new silicone process aid was discovered that shows a significant reduction in surface roughness of both ethylene‐octene and ethylene‐hexene LLDPE copolymers. Beneficial effects on extruder parameters, such as reduction of pressure and current, were also observed.
The effect of low levels of plasticizer on the rheological and mechanical properties of polyvinyl chloride/newsprint‐fiber composites
Authors: Matuana Laurent M. , Park Chul B. , Balatinecz John J.
Published: April 2004

Plasticizers play a key role in the formulation of semirigid and flexible PVC and in determining their physical properties and processability. This study examines the effects of the low phr levels of plasticizer (DOP) on the rheological and mechanical properties of rigid and semi‐rigid PVC/newsprint‐fiber composites. Mechanical and rheological properties of unfilled PVC compounds and PVC/newsprint‐fiber composites at 45 phr were compared over the range of 0 to 15 phr of DOP plasticizer. Analyses of data using SAS procedures of ANOVA were also conducted to discern the effects of concentration of plasticizer on these properties. The following conclusions were reached: (1) DOP was relatively ineffective in improving melt flow index of the composites compared to unfilled PVC. (2) The composites were significantly inferior in tensile strength at yield and stiffer than unfilled PVC. The differences observed were roughly the same over the DOP range studied. (3) Elongation at break and toughness (break energy) were lower for the composites and were essentially independent of DOP level, whereas there was a significant improvement for unfilled PVC over the DOP range studied. (4) Impact strengths of the composites and unfilled PVC were essentially comparable up to about 11.25 phr of DOP. However, at 15 phr DOP, impact strength of the composite was far inferior to that of unfilled PVC. (5) The well‐known antiplasticization effect was noted for unfilled PVC, as well as to some extent for the filled PVC.
Accelerated test method for resistance of plastics to nitrogen dioxide
Authors: Brilliant Stuart Donald , Bacaloglu Ilze , Croce Michael
Published: April 2004

The discoloration produced by the exposure of plastics to a polluted atmosphere containing nitrogen oxides and other gases is well known. New formulations with increased resistance to such discoloration require reliable accelerated tests for characterization of additives and products. The new procedure is based on an exposure of plastics to an atmosphere with a controlled concentration of nitrogen dioxide and evaluation of subsequent discoloration by optical measurements.
The compression set of plasticized PVC
Authors: Rehm Torsten
Published: April 2004

Plasticized PVC shows a surprising degree of elasticity. The reason is that during processing a gel structure is formed in which plasticizer‐stable PVC microcrystallites serve as nodes for the network. The formation of these microcrystallites and their effects on the flexibility of plasticized PVC are examined by means of differential scanning calorimetry (DSC) and measurement of compression set (C‐set). The C‐set of plasticized PVC below temperatures of roughly 130°C cannot be attributed to irreversible flow processes. It is explained by assuming the superimposition of a network formed during processing on a new network formed under deformation. This model allows a plausible description of the influence of temperature, time, plasticizer content, a quantitatively correct calculation of the C‐set of pre‐deformed specimens and an interpretation of annealing effects on the elastic behavior. It is shown that appropriate pre‐treatment can reduce the C‐set of plasticized PVC to below 50%, even for service temperatures of 70°C and above.
The influence of compositional variations in compounded thermoplastic olefins (TPOs) on the physical and mechanical attributes of injection molded plaques
Authors: Ryntz Rose A.
Published: April 2004

Compounded TPO continues to make inroads into automotive applications because of the excellent price/performance balance reached in this thermoplastic substrate. Thermoplastic olefin (TPO), a blend of elastomer and poly(olefin), achieves its balance of properties through the choice of compounded ingredients. The injection molding conditions through which the desired plastic part is achieved are known to also influence the attained properties of the blend. In this paper, the influence of poly(olefin), namely poly(propylene) homopolymer, and elastomer utilized in the compounded blend, in conjunction with molding properties used to produce plaques, are studied as they relate to the physical and mechanical properties achieved. Paint adhesion and friction induced paint damage resistance of coated plaques are shown to be directly related to poly(propylene) molecular weight and elastomer crystallinity. Molding conditions, mainly influenced through the shear induced injection molding process, are also correlated.
Nontoxic replacement for Karl Fischer moisture analysis of plastics
Authors: Raisanen Walfred R.
Published: April 2004

A newly developed automatic moisture analyzer for the plastic molding industry has a detection limit of 10 micrograms of water. Test results are available in three to six minutes. No reagents are used, and instrument setup and calibration takes less than ten minutes. Validation tests show moisture determination accuracy of better than 2% standard error, and precision (coefficient of variation) of 0.5 to 10%. The range of applicability is 10 ppm to 10% moisture.
Mode of action of surface active slip and antiblocking additives
Authors: Sharma Ashutosh H. , Beard Bruce C.
Published: April 2004

The surface concentration and structure of oleamide slip additive and stearamide antiblocking additive commonly used in polyolefins has been investigated by X‐ray photoelectron spectroscopy. The oleamide has been found to form a complete continuous thick layer on the surface of the polymer, whereas the stearamide results in an incomplete discontinuous layer of lesser thickness. Such surface structures are intuitively consistent with the observed action of these molecules in practice. Migration rates of the two long chain amides were found to differ, with the oleamide appearing at the surface at a rate about three time greater than the stearamide. Time dependent surface oxidation of the oleamide additive was observed. It is speculated that the unsaturation within the oleamide molecule is the site of oxidation.
Mechanical properties and dispersion behavior of composite materials compounded with surface treated titanium dioxides
Authors: Hamamoto A. , Tanaka T. , Kinoshita M.
Published: April 2004

The mechanical properties of polycarbonate compounded with titanium dioxide are investigated. Titanium dioxide treated with methyl polysiloxane on alumina silica coating is compounded into the polymer by using a twin screw extruder. Izod impact strength of this composite material is higher than that of the composite material compounded with untreated titanium dioxide. The dispersibility of this treated filler is evaluated by fracture surface and turbidity of the solution of the composite materials. The results suggest that the composite material compounded with titanium dioxide treated with methyl polysiloxane and alumina silica has higher dispersibility. Also, the melt viscosity of the composite material shows the same behavior as that of neat polycarbonate. This result suggests that the melt viscosity is affected by the dispersibility of the particles.
Production of electrically conducting plastic composites by three‐dimensional chaotic mixing of melts and powder additives
Authors: Danescu R. I. , Zumbrunnen D. A.
Published: April 2004

Extended micron‐scale structures were produced in thermoplastic melts from initially large clusters of conducting carbon black particles transported by three‐dimensional chaotic mixing. The structures formed extensive networks that were captured by solidification and rendered the materials electrically conducting. In essence, percolating structures were constructed in situ in lieu of being the result of chance associations among particles. A systematic study was carried out to assess the influence of key parameters and to relate the electrical properties to the microstructures. Micrographs showed complex structures exhibiting patterns characteristic of chaotic advection. Electrical measurements indicated that conductivity was achieved at carbon black concentrations significantly lower than those achievable by common mixing methods and lower than those reported recently for two‐dimensional chaotic mixing.
Aging modifiers for extruded LDPE foam
Authors: Dieckmann Dale , Holtz Ben
Published: April 2004

Aging modifiers help to regulate the isobutane/air interchange in LDPE foams. In the absence of sufficient modifier, the foam will shrivel and collapse. Several glycerol esters are evaluated at four use‐levels for dimensional stability of the foam, antistatic properties, and additive “rub‐off.” Stearamide is compared at one‐use level. Only the glycerides provided antistatic protection, and a distilled monoglyceride made from fully hydrogenated tallow had the best overall performance.
Challenge to fortyfold expansion of biodegradable polyester foams by using carbon dioxide as a blowing agent
Authors: Park Chul B. , Liu Yuejian , Naguib Hani E.
Published: April 2004

This paper presents a new foaming technology using supercritical carbon dioxide as a blowing agent to obtain large volume expansions of biodegradable polyester foams of over fortyfold. The basic approach for the promotion of a large volume expansion ratio with carbon dioxide was to prevent cell coalescence by using a branched material, to dissolve carbon dioxide completely in the melt by promoting convective diffusion under a high processing pressure, to reduce the diffusivity of gas by lowering the melt temperature, and to optimize the processing conditions in the die to maximize volume expansion. The desirable composition of the materials includes dehydrated branched biodegradable polyester (polybutylene succinate), CO2(blowing agent), and tale (nucleating agent). A single‐screw extrusion system was used for foam processing. A large volume expansion ratio of up to forty‐fivefold was achieved from the biodegradable polyester foams. The morphologies and volume expansion ratios of biodegradable polyester foams at various processing temperatures and pressures were studied.
New light stabilizer for coextruded polycarbonate sheet
Authors: Botkin James H. , Schmitter Andre
Published: April 2004

Weatherable polycarbonate sheet can be produced by coextruding a cap layer containing a UV absorber over a minimally stabilized bulk layer. A new UV absorber based on hydroxyphenyltriazine chemistry has been developed that is especially suited to this application. The product provides superior long term weatherability because of its strong UV absorbance and its excellent photostability. It is also relatively nonvolatile and has only a minimal effect on melt viscosity.
TiO2 pigment structure and kinetics of PVC weathering
Authors: Gesenhues Ulrich , Hocken Jörg
Published: April 2004

The influences of doping the core of TiO2 pigments with Al2O3 and of various inorganic surface modifications on the rate of poly(vinyl chloride) (PVC) weathering are investigated. The kinetics of loss of gloss are transformed into photooxidation rates by using Weibull statistics of failure, and a scheme of two consecutive reactions is fitted to the intermediate losses of brightness observed for the most photoactive pigments. When Ca/Zn stabilizers in PVC are exchanged for Pb stabilizers, gloss degradation rate doubles, and the energetic spread of irradiation defects broadens. No indications for specific interactions between pigment and stabilizer are found.
Increasing PVC suspension polymerization productivity by using temperature‐programmed reactions
Authors: Longeway George D. , Witenhafer Donald E.
Published: April 2004

Vinyl chloride polymerizations are known to be autoaccelerating. The reaction rate increases with conversion. Because of this phenomenon, substantial reactor productivity at early conversion can be lost because the heat‐removal capacity of the reactor is not fully utilized until near the end of the polymerization. For this reason it is desirable to speed up the polymerization at the beginning and slow it down near the end. This rate adjustment can be achieved by running the polymerization hotter in the beginning and then cooling. We have written a scientifically based computer model of the polymerization designed specifically to simulate such temperature‐programmed reactions. The model does a complete heat balance on the polymerization, has a molecular weight predictor, and will be described and demonstrated for a polymerization at 50°C using sec‐butyl peroxydicarbonate (SBP) as initiator. By using this single initiator and a very simple straight‐line temperature‐programmed reaction, the time to 80% conversion can be reduced from 335 minutes to 240 minutes. This is a substantial increase in productivity.
Improved organotin stabilizers: Continuing health and environmental research
Authors: Murphy Sandra R. , Bertelo C. , Ringwood R. , Cochran M.
Published: April 2004

Years of experience and significant research support the use of organotin mercaptides as PVC stabilizers. Safe use of organotin stabilizers involves following Material Safety Data sheet instructions and using adequate engineering controls and/or personal protective equipment. Modifications of stabilizers to develop more efficient formulations continue, Product stewardship includes continued development of data to improve our understanding of the effects of materials. An overview of stabilizer trends in the industry, existing data, and planned health/environmental research is presented.
A new processing aid for the extrusion of polyolefins
Authors: Yip Franky , Hatzikiriakos Savvas G. , Clere Thomas M.
Published: April 2004

The influence of a new processing additive (a composition of fine particles of boron nitride) on the rheology and processability of molten polymers is studied. The equipment used includes both an Instron capillary rheometer with special annular dies (Nokia Maillefer wire coating crosshead) attached to the rheometer and a parallelplate rheometer. Two metallocene polyethylenes with several types of boron nitride powders varying in particle size distribution are tested at various concentration levels. The powder having the finest particle size was found to have the greatest influence in the processing of polyolefins using crosshead dies and tips. As a result, its use eliminates surface melt fracture and postpones the critical shear rate for the onset of gross melt fracture to significantly higher values depending on the additive concentration. The performance of the boron nitride in eliminating melt fracture is compared with that of a typical fluoroelastomer. It is shown that boron nitride is a superior processing aid.
High‐performance phosphite stabilizer
Authors: Stein Daryl , Stevenson Don
Published: April 2004

The initial rates of air oxidation of eight aromatic phosphites were measured at 200°C in hydrocarbon solvents. The phosphites were oxidized to the corresponding phosphates, and, in every case, a small amount of the corresponding substituted phenol was also detected. The phenolic compounds likely arose from hydrolysis of the phosphites by water generated during oxidation. In general, alkyl substitution caused a decrease in the rate of oxidation. Phosphite 7 [bis(2,4‐dicumylphenyl) pentaerythritol diphosphite] and, to a lesser extent, phosphite 6 [bis(2,6‐di‐t‐butyl‐4‐methylphenyl) pentaerythritol diphosphite] had a combination of high rate of oxidation and good resistance towards hydrolysis in the bulk state, a combination that is not usual with most commercially available phosphites (1).
Combustion products of lead stabilizers: Dibasic lead phthalate
Authors: Grossman Richard F.
Published: April 2004

The volatile products of combustion of dibasic lead phthalate in air were found to be complex and unanticipated. In addition to phthalic anhydride and water, decomposition products anticipated from TGA studies, actual combustion yields salicylic acid, apparently from decarbonylation. The presence of basic lead acetate, from acetic acid catalysis in the preparation of dibasic lead phthalate, leads to minor amounts of dehydroacetic acid and 2‐hydroxyacetophenone.
Viscosity effects in rigid PVC
Authors: Berard Mark T.
Published: April 2004

The viscosity of PVC is better understood if the material is treated as a fluid which contains filler. Anomalous effects such as die swell increasing with increasing melt temperature and melting history causing changes to the viscosity can be explained if the PVC primary particles are viewed as filler which disappears during melting. The fusion torque peak is well‐described by this approach. The compaction minimum is a free‐flowing powder which changes to a filler‐containing viscous liquid. If another viscous liquid is added to a PVC compound, then the fusion peak will be at a lower torque, because the effective level of filler is reduced. This reduction helps to explain the fusion curve of PVC compounds that contain chlorinated polyethylene (CPE) impact modifier.
Unique benzoate plasticizer for reducing viscosity and fusion temperature
Authors: Bohnert T. , Stanhope B. , Gruszecki K. , Pitman S. , Elsworth V.
Published: April 2004

Plastisol viscosity reduction and control is an important property specification in many vinyl plastisol formulations. A unique benzoate plasticizer is under development that functions as a viscosity reducer. It also is a highly solvating plasticizer in standard plastisol systems. Data are presented on the effects of the new benzoate plasticizer on the properties of phthalate‐ and benzoate‐containing plastisols and vinyl sheet.
New generation of high‐performance PVC alloys
Authors: Weng Dexi , Andries John , Saunders Keith , Macaluso John , Brookman Robert
Published: April 2004

Newly developed alloys of flexible poly(vinyl chloride) (PVC) and polyolefin elastomers have been shown to exhibit improved physical properties compared to those of conventional flexible PVC control compounds. In particular, the new alloys display enhanced electrical properties, better high temperature stability, greater low temperature flexibility, and superior gas barrier properties. In addition, this study demonstrated that PVC/polyolefin rubber alloys have potential utility in many applications where conventional flexible vinyl compounds do not meet certain end‐use performance requirements.
Hot‐tool and vibration welding of poly(vinyl chloride)
Authors: Stokes Vijay K.
Published: April 2004

The weldability of poly(vinyl chloride) (PVC) is assessed through hot‐tool and 120‐Hz vibration welds. Equivalent strengths have been demonstrated for welds made by both of these welding techniques. For two grades of PVC, relative weld strengths of 85 and 97%, with corresponding failure strains of about 2.5 and 3.3%, respectively, have been demonstrated.
Gloss control in rigid PVC—Part I. Techniques for gloss assessment of rigid PVC profiles
Authors: Rabinovitch Elvira , Harshbarger Deanna , Isner James
Published: April 2004

This paper describes various techniques for assessing the gloss of PVC extrudates. It discusses the effect of the incident light angle on measured gloss values and the test sensitivity. It also describes the relationship between surface gloss and extrudate roughness, as analyzed by scanning electron microscopy and optical microscopy. Finally, this paper provides recommendations on the most suitable methods for assessing the gloss of PVC extrudates.