Studies On Some Technological Properties Of New Egyptian Cooton Varieties:

Mohammed Raoof Abdelaliem

The present investigation was conducted for the following aims: (i) to driveequations for predicting the physical properties of cotton yarn from the physicalproperties of the cotton fibers from which this yarn was spun, in view to helpcotton breeder, trader and spinner, (ii) to find out the effect of some processingvariables, namely, yarn count, twist multiplier, carding and combining as well ascotton variety and their interactions on the physical properties of the cotton spunyarns, (iii) to compare the new and relatively older varieties with respect to qualityand spinning performance, and (iv) to propose the best end uses for raw cottonfibers and cotton spun yams dealt with in this investigation.The raw cottons used were the relatively older Giza 75 and new establishedGiza 83 and Giza 85 long-stapled varieties (LS), as well as the relatively older Giza70 and Giza 77 and the new introduced Giza 84 extra long-stapled cotton varieties(ELS). Twenty kg bulk sample from each of Giza 83, Giza 84 and Giza 85 newintroduced varieties were provided by the Cotton Maintenance Researchdepartment, meanwhile 20 kg bulk sample from each of the relatively older Giza70, Giza 75 and Giza 77 were provided by the Cotton Breeding ResearchDepartment, CR!, ARC, Giza. Fiber and yam tests as well as spinning wereconducted at controlled atmospheric conditions of temperature (20°C±2) andrelative humidity (65%±2). The results of fiber and yam physical properties weresubjected to statistical analysis techniques for simple correlation coefficients,forward selection statistical procedure for dependent variable according to SAS(1988). The results for the effect of the processing variables were analyzed forvariance. The comparison between new and old varieties were treated throughvariation parameters, comparison with the world yam levels as well as percentageIincrease and decrease of the new varieties with respect to the relatively oldervarieties. The most important results achieved could be summarized as follows:1. Contribution of fiber to yarn physical properties1.1. The longer, the more uniform the fiber length distribution, the higher thefineness/maturity of the fibers, the stronger and the more extensible thebundles of the fibers. However, the bundle stiffness and toughness didnot show de t;inite trend with either length or fineness/maturitymeasurements which is difficult to be interpreted physically.Nevertheless, the relationships differ from LS to ELS and to LS+ELScategories.1.2. The more even the less imperfected, the less variable in strength andextension, the stronger, the more extensible and toughier the cardedyams spun from LS, ELS, LS+ELS varieties and the combed yarns spunfrom ELS varieties. However, the stiffness behaved differently from LSto ELS to LS+ELS carded to ELS combed yarns.I1.3. Based on the values of’r’s between various yarn properties, it was seenthat the best three physical properties of spun yarn to be predicted fromthe’ fiber physical properties were; yam strength, evenness and nepcountl100 meters.1.4. The best equation for predicting the strength of 405 and 60s carded LSyarns from group 1 and group 2 of fiber properties were equations No.7, 14, 20 and 29, respectively. Meanwhile, the best equations forpredicting strength of 60s and 100s ELS carded yams from group 1 andgroup 2 of fiber properties were equations No. 32, 45, 52 and 62,respectively. The fiber properties required to predict yam strength differfrom one count to another and from one length category to another.IS S . 1.5. The evenness of LS 40 and 60’ carded yams were best predicted fromgroup I and group 2 fiber properties by equation No. 69, 74, 81 and 92,respectively. Meanwhile the evenness ofELS 60S and 100s carded yamswere best predicted from group 1 and group 2 of fiber properties byequations No. 99, 106, 112 and 117, respectively. However, the fiberproperties needed for predicting yam evenness differ from one count toanother and from LS to ELS in case of any group of fiber properties.1.6. The nep count/IOO meters in LS 405 and 60S carded yams could besafely predicted from group 1 and group 2 of fiber properties byequations No. 125, 131, 139 and 145, respectively. whereas the nepcount of ELS 60S and 100s carded yarns were best predicted from group1 and group 2 of fiber properties by equations No. 151,157,167 and176, respectively. Similarly, the fiber variables included in the predictionequations in case of group 1 and group 2 of fiber properties differ fromone count to another and from LS to ELS categories.2. The effect of variety and processing variables on the physicalproperties of cotton yarns.2.t. For LS category, Giza 75 produced the strongest, the more uniform instrength, stiffer and more even and the lowest in thick places, followedby Giza 85 and Giza 83 yarns. The varieties ofELS category take theabove descending order as Giza 84, Giza 70 and Giza 77.2.2. The strength, elongation % and evenness decreased with increasing thefineness of the yam. Nevertheless, the strength and elongation %variations as well a the number of imperfections increase with increasingthe yarn fineness.I168 •2.3. The trend of twist with strength, strength and elongation %variationsand imperfections differ from LS to ELS carded or combed yams,possibly due to the differences in optimum twist from one category toanother and from carded to combed yarns.2.4. The variety x count interaction exerted significant effect on all tensileproperties except the strength and elongation of LS and ELS cardedyams and the stiffness of ELS combed yams. However, the trend Idiffered from one variety to another. On the other hand, the unevennessand imperfections increased with increasing the count of LS and ELScarded and combed yams.2.5. The variety x twist multiplier interaction exerted significant effects onstrength, strength variation and toughness ofLS carded yams. Giza 8Sshowed the best response to twist and was toughter and more even thanGiza 75 and Giza 83, possibly due to the differences between thesevarieties in optimum twist multiplier. For ELS carded yams, the trenddiffered from one yam property to another. For ELS combed yams, theeffect was only significant on the strength variation.2.6. The count x twist multiplier interaction exerted significant effects onstrength and elongation variations and evenness of ELS carded yamsand on the imperfections ofLS and ELS carded and combed yarns.1.7. The second order variety x count x twist multiplier interaction exertedsignificant effects on strength and elongation variations as well as thickplaces and neps ofELS yarns. However, the effect was only significanton the imperfections and evenness of LS yarns.3. Comparison between new introduced and older commercial varietiesboth Giza 70 and Giza 77. Nevertheless, Giza 84 was stronger and moreextensible than Giza 77 and lower in stiffness higher in toughness thanGiza 70 and Giza 77.3.4. Similar to the trend of the physical fiber properties, Giza 75 carded yamsshowed superiority of yam physical properties over those of Giza 85yams which was better than Giza 83 yams.3.5. Giza 84 carded yams, in most cases were superior in tensile properties,evenness and less inperfected than both Giza 70 and Giza 77 yarns,possibly due to the superiority of most fiber physical properties with theexception of fiber length.3.6. Giza 84 combed yams were superior in all yarn physical properties thanthose of both Giza 70 and Giza 77 combed yams, which is likely due tothe superiority of fiber properties of Giza 84 over those of Giza 70 andGiza 77 varieties./3.7. In conclusion, the attention of cotton breeder and technologist must beattracted to more emphasis in breeding within the LS category.However, their role within ELS category is highly appreciated .4. Proposed end uses for raw cottons and cotton spun yamsVarious end uses were proposed for the different raw cottons and spun yarnsdealt with in the present investigation based on their physical properties as well asthe recent technologies, presently applied.