Woven Polypropylene Research Articles

All-polymer composites from recycled woven polypropylene fabrics and polyethylene film

Woven polypropylene fabrics are widely used, for example, in sacks for transportation of bulk materials in agriculture and construction. There are several important end-of-life issues with these and at present the majority of these sacks are landfilled in the UK. A new process has been developed to convert these into fully recycled all-polymer composites by incorporating waste polyethylene film as the “matrix” material. The effects of lay-up arrangement, fibre orientation, extent of cleaning and drying, processing temperature, pressure, and time were all investigated. Mechanical properties of the samples were determined using a combination of flexural, tensile, and impact testing, coupled with optical and electron microscopy. The recovery of orientation of the polypropylene tapes during heating was investigated as was the bonding between the materials. It was found that there was a balance between good bonding of the materials (at higher temperatures) versus loss of stiffness because of recovery of orientation. The properties were found to be relatively insensitive to the extent of cleaning and drying that was used. It is expected that these composites will possess good outdoor weathering resistance, and a further advantage is that they will be further recyclable at the end of their lifetime. POLYM. ENG. SCI., 46:1523–1529, 2006. © 2006 Society of Plastics Engineers

Polypropylene Row Covers Greatly Enhance Growth and Production of Fourth-leaf Sweet Cherry Trees

Black, woven polypropylene row covers were compared to chemical sprays as methods to manage ground vegetation in a `Regina'/Gisela 6 orchard planted in 2001. Row covers were installed within 1 month of planting. Exposed row cover width was 2.4 m, with edges (30 cm on each side) buried in the ground. Only a 30-cm band along the edge of row covers was sprayed with herbicide to facilitate mowing. Weed management of control trees consisted of chemical herbicide sprays. Trees were not fertilized since planting in 2001. Irrigation of all trees was applied with low volume (20 L·h-1) microsprinklers and scheduled according to soil water content. Row covers significantly increased trunk cross-sectional area (TCSA) by about 30% annually. By Summer 2004, trees with ground covers had filled their allotted space within rows, while control canopies were ≈50 cm apart. Trees in row covers produced a 130% higher average yield than controls (7.4 kg/tree vs. 3.2 kg/tree). Row covers produced larger and firmer fruit, which matured 2–3 days later than controls. Groundcovers slightly increased soil temperature from April to September by ≈2 °C at 5- and 10-cm depths. Roots under ground covers were denser and more spread out than in controls and water use efficiency was higher for trees growing in ground covers. Amount and labor for herbicide application was reduced to less than half with row covers. Although ground covers are expensive at ≈$2000 per acre, their cost could be offset by earlier and higher production and by long-term savings in labor, water use, and herbicides. Durability of row covers is expected to exceed 15 years.

Characteristics of electrostatic discharges from intermediate bulk container materials

In this work, we have studied experimentally electrostatic discharges from flexible or rigid intermediate bulk container (FIBC or RIBC, respectively) materials charged to both polarities. Four different kinds of materials were investigated, including woven polypropylene (PP) fabric, smooth-surfaced polypropylene sheet, smooth-surfaced polyethylene (PE) sheet and smooth-surfaced nylon sheet for comparison. Discharge peak current, charge transfer and distance from the surface at which a discharge occurred, with no earthed backplane, were measured over a range of surface potential values. According to the results, negative polarity discharges gave higher peak current and charge transferred values than positive polarity discharge of the same surface potential. The distance at which the discharge occurred increased with surface potential as expected. However, peak current and charge values were relatively constant over a range of surface potential.

Multifilament polypropylene mesh for urinary incontinence: 10 cases of infections requiring removal of the sling

One hundred and forty-nine women received a suburethral woven polypropylene mesh insertion for urodynamic stress incontinence. Eleven patients (7.5%) presented between 4 and 17 months after surgery (mean 10 months) with symptoms of retropubic infection. Ten patients required surgical exploration, drainage of the collection and removal of the tape either unilaterally (six) or bilaterally (four). Bacterial cultures were negative in nine women. Following removal of the tape, eight patients reported residual incontinence, either stress leakage (five) or de novo urge incontinence (three). Multifilament polypropylene meshes appear to be more at risk of infection, usually requiring sling removal, which may be related to pore size of the mesh. Our data reinforce the importance of proper evaluation of new surgical procedures by rigorously designed randomised trials with adequate follow up to identify rare but potentially serious complications.

MOISTURE CHANGE OF COTTON BALES DURING STORAGE

The purpose of this research was to determine the moisture transfer and weight gain of universal density cottonbales packaged in different materials. Bagging materials investigated included both woven polypropylene bags withextrusion-coated strips to prevent fibrillation as well as similar bags that were fully coated on the interior to reducecontamination. Three bales each were ginned, packaged, and placed in four different types of bags two types of wovenpolypropylene spiral sewn bags with alternating extrusion-coated and uncoated strips, and two types of fully coated bags.Initial moisture contents averaged 3.6%. The bales were stored for 140 days at 70% relative humidity (RH) and then at 50%RH for 88 additional days. Bales were weighed and measured for thickness twice each week. After 140 days, the strip-coatedbales averaged 6.9% moisture and the fully coated bags averaged 5.3%. After an additional 88 days of storage at 50% RH,the strip-coated bales averaged 5.9% moisture and the fully coated bags still averaged 5.3%. The bales in the fully coatedwoven polypropylene bagging changed moisture much more slowly than those bales in the strip-coated materials. Balethickness changed from as little as 0.3 cm (0.1 in.) to as much as 2.2 cm (0.8 in.) as moisture content changed for the balesin the four types of bagging. Fiber quality did not change during storage.

Impregnation of Hydroxy-Anthraquinone Compounds into Polypropylene Fabrics by scCO2 and the Sorption Ability for Metal Ions

Woven polypropylene fabrics were impregnated with hydroxy-anthraquinone (HAQ) derivatives compounds by supercritical carbon dioxide where the HAQ worked as a dyestuff. The HAQ-impregnated fabrics were tested to adsorb metal ions dissolved in water forming the “dye-metal chelate” under specific conditions of pH for one selected metal ion. The metal ions are believed to be trapped around the HAQ molecules by the hydroxyl groups, working as a mordant dyeing.

Effects of Slope and Underlay on Surface Runoff of Irrigation from Woven Polypropylene Groundcloth

Woven polypropylene groundcloth is used extensively in plant nurseries as a permeable and durable surface for container plant production. To better understand the fate of overhead sprinkler irrigation water, we designed and constructed runoff platforms (2.7 m2) to measure runoff and leachate from single irrigation events as affected by slope and underlay substrates. Groundcloth-covered platforms at slopes of 1.5% and 11% were tested with each of five underlay treatments: no underlay, coarse sand, 50% coarse sand and 50% no underlay (CS50), gravel, and native sandy soil. We applied 0.9 cm of irrigation at 1.8 cm·h-1 and determined runoff and leachate volumes. Runoff percentage [runoff × 100%/(runoff + leachate)] increased at the 11% slope for each underlay treatment. Mean (n = 10) runoff percentages (RP) for the 1.5% and 11% slopes were 0.5% and 15.7%, respectively, for no underlay, 0.1% and 1.1% for coarse sand, 0.1% and 0.7% for CS50, 0.7% and 2.5% for gravel, and 0.1% and 3.1% for native sandy soil. The low RP observed indicate that a high percentage of nutrients and agrichemicals associated with container leachate would move into the underlying substrate or soil rather than directly running off into surface waters.

Storage practices and aflatoxin B1 contamination of ‘egusi’ melon seeds in Nigeria

AbstractIn the rain forest and northern guinea savanna of Nigeria, melon seeds in farmers' stores are usually kept in woven polypropylene bags, or less often in jute sacks. Seed mouldiness was the main storage problem and when farmers noticed it, they brought the seeds out for redrying and sorting. Aflatoxin B1 contamination was detected at levels above 5µg/kg in 35.6% of the forest and 27.4% of savanna samples with mean levels of 13.7 and 12.1µg/kg respectively. The incidence of diseased seeds positively correlated with levels of aflatoxin B1. The samples stored for up to two months did not contain detectable levels of aflatoxin, but thereafter the incidence and level of aflatoxin increased. Copyright © 2004 Whurr Publishers Ltd

Effect of a Synthetic Fabric Row Cover on Soil Moisture Content, Growth and Fruiting of Young Sweet Cherry Trees (Prunus avium L. cv. `Regina'/Gisela 6)

A `Regina'/Gisela 6 sweet cherry orchard was planted in April 2001 to evaluate a row cover (RC) made of black, woven polypropylene fabric, in water conservation. Trees were trained to a central leader and planted at 3 m x 5.4 m. Soil water content and tree growth variables were compared for trees growing with or without a 2.4 m-wide RC. Irrigation of all trees replenished approximately 80% of weekly evaporation rate. Trees with RC maintained consistently higher (30% to 40%) soil moisture content at 30 cm depth than non-RC trees. In Spring 2003, trees in RC had significantly larger trunk cross sectional area (34%), height (7%), total wood length (65%), total number of branches (20%) and number of 1-year-old-shoots (45%) compared to trees with no row cover. Length of 1-year-old wood for trees in RC was two-fold that of non-covered trees. In Summer 2003, RC had no clear effect on bloom time, intensity or duration. Fruit yields were light and not affected by RC, but fruit size was slightly larger for trees in RC. Although trees were not fertilized, foliar nitrogen content was significantly higher and leaf green color was notably darker green for trees with RC. During Spring and Summer 2003, soil temperatures under RC at 5-cm and-10 cm depths were generally 1 °C to 2 °C warmer than in non-covered ground. The RC did not affect air temperature at 10 cm and 30 cm above ground. It is speculated that RC promoted tree growth by a combined increased available soil moisture and warmer root temperatures, which favor root development and nutrient uptake, particularly in the absence of competing weeds. Increased branching in trees with RC is unclear. It is possible that light quality above RC triggers developmental changes resulting in increased vegetative budbreak.

Storability of Amaranthus leafy vegetable in different vegetable boxes

AbstractFresh Amaranthus sp. leafy vegetable was stored in cane boxes lined with polyethylene or woven polypropylene or unlined boxes, all covered with moist jute. Open‐air storage on laboratory benches was the control. The vegetable in boxes stored well for 3 days without loss of acceptability, but discolouration and rotting were obvious by the sixth day. The leaves stored in open air were of moderate quality within a day and unacceptable. Returns from using the boxes were N79‐80 per day, compared to rental cost of N20‐21.4 per day. Copyright © 2004 Whurr Publishers Ltd

Effects of different ground vegetation management systems on soil quality, growth and fruit quality of culinary apple trees

SummaryContact and residual herbicide, polypropylene woven (plastic) and straw mulches were compared as ground vegetation management systems in a newly planted Bramley/M.9 apple orchard at HRI-East Malling, UK over an eight year period. The effects of these treatments on weed control, soil quality, tree nutrition, tree growth, crop yield and fruit quality were measured. Contact herbicide gave the poorest weed control, followed by residual herbicide.Very little weed intrusion occurred in the plastic and straw mulch treatments. The concentrations of soil biomass C, biomass N and respiration rates were consistently greatest under the straw mulch and contact herbicide, suggesting that C and N was incorporated into the soil biomass most efficiently under these treatments. Soil solution nitrate concentrations also were lowest under straw mulch and contact herbicide. The straw mulch increased the concentration of K in the surface soil (0–15 cm) compared with the other treatments, and this was reflected by consistently higher concentrations in the leaves of trees. The contact herbicide treatment had lower leaf concentrations of N in most years. Fruit mineral concentrations reflected leaf mineral concentrations. Trees growing in the straw mulch had the greatest shoot growth and those in the contact herbicide treated soil had the least. These increases are ascribed to the greater conservation of moisture within the profile during the shoot extension period. Differences in harvest yield between treatments were generally small in individual years, however cumulative differences occurred over six crops. Trees in the straw mulch had the greatest yields and mean fruit weights. The ground vegetation management systems did not influence fruit quality except in the second harvest, when yields were low and the individual fruit were large.

IMPACT OF ADDING MOISTURE AT THE GIN LINT SLIDE ON COTTON FIBER QUALITY

The purpose of this research was to determine if moisture applied before packaging caused cotton fiber degradationduring subsequent storage. Fiber quality characteristics of universal density cotton bales were determined before andafter extended storage (months) in three separate studies. For the test bales, water was sprayed over the top of the fiber asit came down the lint slide after ginning and cleaning. The bales were then packaged at universal density and placed in eithertripled polyethylene bags, woven polypropylene bags, or fully coated woven polypropylene bags, and then stored at atmosphericconditions. Bale moisture content after the water was added ranged from less than 5% to over 15% w.b. The baleschanged weight and moisture content substantially during storage depending on the type of bale covering and the initial balemoisture content. Most fiber quality characteristics except color remained about the same. The HVI color decreased fromMiddling (31) before storage to as low as Strict Low Middling Spotted (43) after storage depending on moisture content. OtherHVI data changed slightly during storage regardless of the moisture level. The higher initial bale moisture contents resultedin greater degradation in color. Based on these studies, cotton bales should not be stored at moisture contents above 7.3%w.b. regardless of bale covering materials.

Conditioning factors of iron ochre biofilm formation on geotextile filters

This paper presents a study of ochre formation on geotextile filters. Ochre is a substance found sticking to solid surfaces of drainage systems and may cause clogging. Ochre formation is discussed based on the new concepts of biofilm development. Ochre formation is the result of microbial colonization and its affinity to iron compounds naturally found in seepage water. The aerobic–nonaerobic interface in drainage systems is a very favourable locale for optimum development of iron bacteria. Laboratory studies were done to verify the influence of intrinsic characteristics of the geotextiles and environment on ochre formation. Because flow condition was not considered in the tests, however, these results may not represent real field performance of geotextile filters. Tests of biofilm formation were conducted in Erlenmeyer flasks containing culture mediums for iron bacteria and geotextile samples. Nonwoven polyester, nonwoven polypropylene, and woven polypropylene geotextiles were used in the tests. The study was performed considering different levels of iron concentration, available dissolved oxygen, and pH. Laboratory tests have shown the fundamental importance of iron bacteria activity, type of geotextile, and environmental conditions on ochre formation.Key words: ochre, clogging, filtration, biofilm, geosynthetics.

Cation‐exchange fabric prepared by electron beam‐induced graft copolymerization of binary monomer mixture

AbstractApplying the electron‐beam preirradiation method in air the cation ‐ exchange fabric (CEF) containing sulfonic acid (R‐SO3H) groups was prepared by graft copolymerization of sodium styrenesulfonate with acrylic acid onto non woven polypropylene fabric. The effect of reaction conditions on the grafting yield and reaction mechanism was examined.The ion‐exchange properties towards Cu(II) and Co(II) ions of the CEF were investigated depending on the form of the CEF and a pH of the solution. It was found that the synthesized CEF contains both strong acid groups (R‐SO3H) and weak acid (R‐COOH) groups in almost equal proportion. The utilization of the CEF in Na+ form allows to make the best use of its ion‐exchange capacity.

Artificial graft slings at the midurethra: physiology of continence.

Surgeons have performed multiple variations of the pubovaginal sling procedure in an attempt to achieve reproducible results. In this review, the potential mechanisms by which midurethral slings restore continence are discussed. Surgical techniques are described and the results of recently published data in the literature are presented. Two midurethral slings, which employ loosely woven polypropylene mesh, are the tension-free vaginal tape (Ethicon Inc., Sommerville, NJ) procedure and the SPARC Sling System (American Medical Systems, Minneapolis, MN). They are used in this article to illustrate important clinical concepts.

Filter press plugging in zinc plant purification circuits

Mineralogical studies were carried out to identify the causes of filter press plugging in two zinc plant purification circuits. In the first circuit, Kraft paper covers were used over the filter cloths. An extensive layer of basic zinc sulfate, Zn4(SO4)(OH)6.xH2O or Zn5(SO4)2)(OH)6.xH2O, precipitated on the surface of the Kraft paper and within the pores of the paper. In the second circuit, woven polypropylene cloth was used in the first-stage filter presses. The cloth was extensively covered by basic zinc sulfate, which also filled the relatively large pores in this type of material. An unwoven polypropylene cloth was used in the second-stage filter presses of this circuit. The significantly finer pores in this type of cloth appeared to be plugged by major amounts of zinc sulfate, ZnSO4.xH2O, that presumably crystallized because of the temperature-concentration conditions prevailing in that part of the circuit.

Mulches and Biosolids Affect Vigor, Yield and Leaf Nutrition of Fertigated High Density Apple

`Spartan' apple (Malus×domestica Borkh.) trees on M.9 (T337) rootstock were planted in April 1994 at 1.25 m × 3.5 m spacing. Seven soil management treatments were applied within a 2-m-wide strip centered on the tree row and arranged in a randomized complete-block experimental design. Treatments included a weed-free strip (check) maintained with four annual applications of glyphosate; surface application of 45 t·ha-1 of Greater Vancouver Regional District (GVRD) biosolids applied in 1994 and again in 1997; mulches of shredded office paper; alfalfa (Medicago sativa L.) hay; black woven polypropylene; and shredded paper applied over 45 t·ha-1 GVRD-and Kelowna-biosolids applied in 1994 and 1997. All experimental trees were fertigated with phosphorus (P) in the first year and with nitrogen (N) annually. Cumulative yield for the first five harvests was higher for trees subjected to any soil management treatment relative to check trees. Maximum cumulative yield, exceeding check trees by 80%, was measured for trees grown with a shredded paper mulch with or without biosolids application. Trees from the three shredded paper treatments were the only ones significantly larger than check trees after six growing seasons. No increases in leaf nutrient concentration were consistently as sociated with improved tree performance. Notable effects included increased leaf P concentration associated with biosolids application, increased leaf K concentration after alfalfa mulch application and temporary increases in leaf Zn and Cu concentration associated with application of biosolids high in Zn and Cu. Use of both mulches and biosolids amendments benefits growth of trees in high density plantings despite daily drip irrigation and annual fertigation.

Produção de repolho branco chinês (pak choi) sob proteção com "não tecido" de polipropileno

O cultivo do repolho branco chinês (pak choi) (Brassica campestris var. chinensis) foi avaliado nas condições de inverno dos Campos Gerais (PR), sob proteção, com "não tecido" de polipropileno branco, também conhecido como agrotêxtil, nas gramaturas de 17 e 25 g/m², comparado com o cultivo sem proteção. Os híbridos usados foram Canton e Chouyou com semeadura em bandejas de poliestireno expandido em 11/05/00 e transplante no estádio de 4-5 folhas definitivas, em 23/06/00. O delineamento experimental foi de blocos casualizados com 5 repetições, tendo os tratamentos seguido esquema fatorial 3x2. Cada parcela teve 36 plantas distribuídas no espaçamento 0,30 x 0,30m. Após o transplante, nas parcelas respectivas, as plantas foram cobertas com o agrotêxtil como uma manta flutuante. As avaliações na colheita, realizada de acordo com a maturidade das plantas foram: número de folhas, altura da parte aérea, diâmetro da base, peso de matéria fresca e matéria seca de plantas. A porcentagem de plantas com florescimento prematuro foi avaliada aos 51 dias. No cultivo sem proteção, as plantas do híbrido Canton foram prejudicadas pela geada, apresentando os bordos foliares totalmente queimados, enquanto o híbrido Chouyou não teve nenhum sintoma visual de dano por geada. O agrotêxtil protegeu as plantas contra a geada e contribuiu para o desenvolvimento mais rápido das plantas, possibilitando colheita precoce aos 38 dias do transplante quando usou-se gramatura de 25 g/m² e aos 42 dias na de 17 g/m². No cultivo sem proteção, a colheita ocorreu somente aos 46 dias. Entre os híbridos, Canton foi mais precoce que Chouyou. No entanto, Canton foi suscetível ao florescimento prematuro na estação de inverno, apresentando algumas plantas com esta ocorrência aos 36 dias do transplante. A proteção com polipropileno promoveu a produção de plantas com qualidade superior do produto observada através das características de maior peso de matéria fresca e matéria seca, diâmetro da base da planta e altura da parte aérea, quando comparada com o cultivo sem proteção. Entre as gramaturas testadas, destacou-se a de 25 g/m², no híbrido Canton, na característica de precocidade da colheita nas condições de inverno dos Campos Gerais.

Assessment of Microenvironmental Conditions Related to the Use of Synthetic Sheet Mulches for Protecting Newly Planted Trees in Semi-Arid Environments

ABSTRACT Microenvironmental conditions created by six weed control methods and the resulting survival and height growth of two species of windbreak trees were measured in three separate plantings in Nebraska. The treatments included three synthetic sheet mulches commonly used in tree plantings. Climagro, a black polyethylene mulch, and Sunbelt, a black woven polypropylene mulch, improved the growth of green ash (Fraxinus pennsylvanica Marsh.) in two of the three plantings. Survival of green ash and survival and growth of Scotch pine (Pinus sylvestris L.) were not significantly different among the treatments. Positive correlations were found between August soil moisture and ash height growth. No relationship was found between soil temperature and ash growth, although significant differences in soil temperature among treatments were detected. Weed control treatment did not affect air temperature above the soil surface or the amount of mycorrhizal roots on Scotch pine. Economic analyses of the use of Climagro and Sunbelt mulches in a hypothetical green ash windbreak investment resulted in positive returns.

Utilização do 'não tecido' de polipropileno como proteção da cultura de alface durante o inverno de Ponta Grossa - PR

O experimento foi realizado na UEPG, Ponta Grossa, PR. Estudou-se o efeito da proteção com 'não tecido' de polipropileno sobre o desenvolvimento, a qualidade e a produção de três cultivares de alface, transplantadas no inverno de 1998. O delineamento experimental foi inteiramente casualizado, distribuído segundo esquema fatorial 3x2 (cultivares x sistema de cultivo), com 5 repetições. As cultivares utilizadas foram Tainá, Elisa e Verônica, cultivadas sob a proteção do 'não tecido' de polipropileno (PP) e em ambiente natural (AN). O uso do 'não tecido' como proteção de plantas de alface resultou em maior peso de matéria fresca de cabeça para todas as cultivares estudadas quando comparado ao AN. Verificou-se, para as cultivares Tainá e Verônica, incremento do índice de área foliar, com conseqüente aumento da biomassa das plantas produzidas sob o 'não tecido'. A cultivar Elisa apresentou limbo foliar com aspecto de estiolamento, perdendo a turgidez rapidamente após a colheita. Possivelmente, os níveis de radiação sob PP foram inferiores ao ponto de saturação fotossintética para a cv. Elisa. Recomenda-se o uso do 'não tecido' para as cultivares Verônica e Tainá, no inverno, para a região de Ponta Grossa, por apresentarem cabeças com ótima qualidade e peso comercial.